Re open the porch? Minimally paint out the white siding between the Windows a putty color so it isn't such a glaring infill.

Lovely house.

We'd like to add more windows to the sunroom and some doors if our budget allows. But we'd like to keep it as a four seasons room because the extra space is nice to have.

Two more Windows the same size as the existing slipped into the blank section would help tremendously. Depending on your skill set that could be diy. Long term switching out the trim from white to a putty color would help the whole house tie together better.

Your house is beautiful. I'd avoid sliding doors. They won't suit the age or style of the house, and not sure they'd work for the front of the house. I'd just go with new windows across the whole sunroom (that work with the style/age of the home) and make sure you have substantial trim around the windows.

With your budget, I would put up a privacy fence near the sidewalk, add a gated arbor entrance and invest in landscaping. It looks like adding doors would require you to break into the brick, which could get pretty expensive. Nice house!

We thought about adding a privacy fence but since this side of the house faces the street it can only be 42 inches high. We definitely like the idea of an arbor. Would there be another solution to adding access to the yard from the sunroom? Maybe french doors? Or a door along the side?

Add 2 more windows or a pair of French doors which would also enhance your interior. An arbor with pillars in the same style as your entry would add architectural continuity and interest to the front of the house. The image Lisa posted above is quite attractive too. I recommend you paint the trim, siding, eaves and pillars a khaki or sage green which would compliment the brick beautifully and and tie all the elements together. As Bricken says, adding landscaping that focuses you towards your front door would make for a more inviting entrance.

does anyone have thoughts about adding shutters to the windows? I was looking through pictures of American Foursquares and some of them have shutters.

Please don't laugh at my lack of photoshop skills...it's been a while haha! Maybe something like this but slightly less decorative windows? And the french doors in the middle?

I would love to paint the brick (please don't yell at me, I know I'm in the minority there but I love the way it looks) but I don't think we would have the money to do that. I've heard of brick staining that leaves the brick porous and lasts over 25 years, but again that's probably not in our budget (we still have some updating to do to our kitchen as well, yikes!)

confused about the entry. How can you direct guests to you door.? sculptural house letters and lamppost . French doors and deck off sun room if allowed could give access to yard or become a main entry.
Shrubs and low decorative fence could add a bit of privacy.

There is a sidewalk/path that leads straight to our front door from the road.

That's perfect, but I don't think it's within your budget. You say the porch was once open- is the original outdoor entrance to the porch on the side? If so, you might be able to add a French door there, but I'd be concerned about the esthetics of another alteration to the addition.

With 5K, I'd consider shutters, removing the plastic and adding windows/moldings similar to lisa0527's suggestion. If that's over-budget or outdoor use is the priority, put the whole thing in landscaping to make the street view and entrance more inviting. Add a patio. Maybe arborvitae or bushes could give you some privacy so you can enjoy the yard.

I like the way brick looks painted, but you will destroy the brick if you do it. Research "brick spalling" before you make any changes.