I forgot to mention there is a fireplace across from the large windows

What are you going to use the space for? Is the piano going to be in the space? Does it need to serve multiple functions?

Need to provide more details, what is your style and do you have any favorite colors and existing furniture?

I would like to keep the piano where it is and maybe move it closer to the wall. Some seating in front of the fireplace and overlooking the valley and our dining room table and chairs will be on the end by the patio doors. Our table is oval and seats 6 without the leaves in it. If you can think of some other arrangement please give me ideas. This room is the only place our table and chairs can go in.

I like the colors you see in fall. I'm traditional in decorating.

No furniture yet for this room except table and chairs that aren't moved in yet

Looking at the middle photo - what is beyond the wall on the right - any chance you can open that up ?

something like in the reference/inspiration would be nice and warm in yr space but on a smaller scale

Nothing could be taken out. We are done remodeling

On both sides of the fireplace is a doorway one to the kitchen and the other to the entry into the house

Think you have the right idea. Put comfortable chairs in front of fireplace or even small settee and single chair diagonal next to fireplace. Large ottoman or coffee table for your feet/drinks. I would angle piano in corner and have facing so "player" can face out into room and toward the room not the wall :). Dining table makes sense where you suggested. Use area rugs to tie together spaces. They don't have to match but should complement each other in color.

Any pictures as to what color area rugs I should use and where?

Even picture ideas of chairs and extra lighting I should get or a drawing of how this room should look

Wait to buy area rug(s) until you have bigger pieces and color selections. The rugs can pull it together for you. I think you need to ask yourself some questions.
Is this just a sitting room (except for dining area)? Meaning will there be a TV or are you just sitting in front of the FP? How many people will be using the space? Do people play the piano for others or just themselves? Do you have children/pets who will be using space?
It looks like the walls are pretty neutral. Is it the same color in the adjacent rooms? You mentioned fall colors. How much color do you like? You could buy more neutral pieces in seating but punch up with color in area rug, throws or pillows. You really need to define WHAT colors make you happy. Greens and oranges work well in your description but do you like more subdued colors or more saturated hues?
How big is space? Hard to tell from picture.
Do you have overhead lighting? Sometimes a little tricky in open floor plans with cords unless you have outlets in floor.
The more you define your wants/needs the more we can help you :)!

One more suggestion :) if you can, put the table and chairs in so we can see size and style, and angle the piano. Also you have awesome windows- do you have a great view we can play off?

I like color. Reds, browns I have off white kitchen cupboards some green. No overhead lighting. A lot of outlets on the walls. Lighting over dining room table is the only spot right now. The wall color is applesauce cake. Below is my dining room table and chairs and floor plan.

How much space is on the back wall of windows? Doesn't look like much. Do you need a lot of seating like a sofa or would 2 chairs work? I would prefer chairs as they are "cozier" and won't block your view.
You will definitely need more lighting then just ceiling fan. Depending on your space and size of chairs, you could put 2 end tables with lamps or accent table in between with floor lamp. Slipper chairs might work well. They are armless chairs, very versatile and comfy :).

I like some green color. Not that I have green cupboards

I was kinda planning on it being a sitting area plus dining area. I play the piano and it's just me and my husband in this house now. He wants a tv in this room, but I think it will be somewhere else

I was thinking a loveseat and 2 chairs. I also like the armless chairs too. No, the wall space between the two windows is not very big.

This is the view from the windows

I love furniture from Pier 1 also

That's beautiful! If you do loveseat you could do ottoman or coffee table in front for feet /drinks, floor lamp on one side, really doesn't look like you have enough space for side tables but you might want to play with that after you get loveseat. There are some smaller options now and ones that even slide into seat. You should also consider some source of light by piano. Sconces could work nicely to frame piano, especially if you have smaller light for lighting your music. Be very careful with the chairs. You could put them diagonally in front of FP but depending on your coffee table this might not work. One on piano side facing in might work but keep it smaller and armless.

Your space reminds me a lot of mine which I've been slowly working on:

https://www.houzz.com/discussions/open-floor-plan-need-help-decorating-dsvw-vd~495810

Some suggestions from people helping me in my post might be useful to you as well.

Ck out the Abbie loveseat at Pier 1. Do you have one near you? I love the curve of it- very cozy! They have a bunch of slipper chairs. Bring measurements with you of the space so you can compare with size in store. Very hard to tell on any electronic true color. Often looks very different in person. Like all the colors the ABbie comes in but you really need to decide if you want to go more neutral with large pieces and accessorize with color.

We do not have a Pier 1 near us. I think I looked at the same sofa. I was thinking neutral for sofa and chairs with pops of color

I didn't read anybody mentioning a back to back sitting area.
A couch facing the fireplace and chairs or even another (same?) couch facing your breathtaking view.
If you do chairs you could do a small round or square coffeetable in between.
My first instinct was putting the piano by the slider, but it might get drafty there...
I read you like Pier1, but now realize you say you don't have one close, but had looked at a few items, perhaps you could order online, but I wold advise with upholstered items, to sit and try them first.
Third or fourth photo for by your dining area

Mirrors by your dining room wall?

A few more fall coloured interiors...
Love the velvet curtains in the last photo!

You have two natural focal points - the fireplace and the view. I would design and illuminate the space outside the windows (foreground and background) and arrange seating inside to take advantage of it as well as the fireplace.

So I just went to the Pier 1 website and it said the sofa was only available in store-bummer! I can personally vouch for the Abbie (selection we discussed and that was posted above :) as I have it in chocolate in my staging inventory. It is good quality for the price and can be used in many different types of decor. Not sure this means anything to you now :(.

I would agree with being cautious purchasing furniture online but if this is your only option, I have a few suggestions.

Read the reviews! The colors on any electronic device often vary dramatically than what they actually are. Reviewers will point this out and comment about quality/value.

Factor in additional shipping costs and worse, return fees.
I have purchased a lot of furniture/accessories from overstock.com. They have $2.95 shipping, free when you spend over $50- on everything-big and small. The customer service is great and the return fees are reasonable. HOWEVER, I am buying for "aesthetics" not quality. I am not spending a lot of money but there are higher priced options of better quality. I can't recommend this for everyday use as this is not how I have used the pieces but certainly most purchasers are not stagers :). Maybe others have experience here.

Do you have any local stores you can visit? I think you are on your way and think getting a neutral loveseat and adding color in accessories is a great option. Can you start there? Is a furniture road trip feasible ;)?

We are thinking going furniture shopping soon, but we were told it would probably be best to move in first, and then see what we have room for.

I will probably be back on when we get the dining room table and chairs in for more ideas. Thanks everyone for your ideas. I have some thinking to do.

I do hope you'll try them in front of the FP, at least for this winter. It will be a cozy place to dawdle over morning coffee or after dinner dessert and plan for a spring attack on the entire space! By then you'll know exactly what you want to do!