It can depend a bit on where the plumbing is on the tub. If it's on the same wall as the toilet, probably easy to remove the wall between the two areas. If it has the plumbing in the wall between the tub and sink, that will require some extra plumbing work.

Other than that, it looks like you probably have space for a shower where the tub is, you can replace the vanity. Looks like a double fold door, you could wall that in to make for a standard door.

The plumbing for the tub and toilet are on the same wall

I’d demo the whole thing including the wall separating the vanity from the tub/toilet area. Do you need a tub or do you want to replace it with a shower only? Do you need a place to sit down and do hair and makeup or would you rather have more storage in the vanity? You’ll want to come up with a budget. What is your style?

ShadyWillowFarm- I want to demo the whole thing. Initially I was wanting a tub, but I feel like the space would feel bigger if we just added a shower. I do not need a space for hair or makeup. I was going to downsize the bathroom vanity and need more storage. The opening is so big for no reason, but if I add more wall there I feel like it would be one long skinny bathroom. I even thought about moving the bedroom door over and adding more space to the bathroom. I like a simple style with a bit of nature. My style is all over the place, but I lean more to boho/farm/spa like designs. This will be DYI other than the plumbing if we plan to rearrange.

You will help yourself tremendously by finding and hiring an experienced interior designer or kitchen and bath designer. This will help keep you from making mistakes.

Otter Play- Im pretty sure I'll need a professional to see what I can or can not do. I have a few ideas and it can go a million different ways.

Wow, what a time capsule! I would start with a scale drawing of the space. If you're not versed in sketch up, then graph paper and pencil will do. People here will be more willing to help with a layout if you have the measurements and everything drawn out. It may help you get your head around how you would prefer to see it. Once you see a floor plan it may help you understand where things make sense and how much space you have.

A designer who focuses on bath design can be a great help also. They can come up with ideas that you may not have even considered - and those ideas usually work better than the average Joe can imagine. Are you doing the work DIY or hiring a contractor? Contractor may be able to give you a reference for a designer or know one who he/she works with frequently.

Susie- thanks for the tip. I would like to do as much as I can myself. I already have a contractor working on making a huge library I have into two bedrooms and a mudroom so I'm trying to save where I can. I understand this may be out of my league though.

You also mention it being a time capsule and you are more than right on that. This place has not been touched since it was built and it's all original to the house. It's crazy to see, but it still has to go (LOL)

I just took a peek at your idea book. You have some lovely designs saved that will make a tremendous impact.

Probably best to have an overall plan before doing any more work. What if you decide later that you need to reclaim space from an area that you’ve already redone? Your style is irrelevant at this point - you need to work out the space planning.

If you have another functional bathroom, start the demo! Wallpaper, mirror, rug (!), vanity. You’re leaving things in the same place, right? Just plan for the contractor to delete this part of wall and add the other part.

Susan- Good points to think about, but the master bedroom is extremely huge. The space I would lose to gain in the master bathroom would still leave me a lot of room in the bedroom.

If you have a lot of space and budget, I would consider moving the door into the room and the big window, then expand the footprint for the bathroom & closet. It seems like you need more space for both. That kind of project does call for a designer, in my mind. Maybe look for a design-build firm nearby?