I am not sure if this is helpful, but we are in the midst of building a house on our ranch. It sounds very similar in design--great room with large living, dining and kitchen area all essentially in one room. I chose a wideplank maple hardwood floor. Had the same concerns as you do about dirt (it's a ranch, after all!), dogs, traffic, etc. Our walls are also off-white with lots of windows and light. THey are being installed next week, so I don't know yet, how they will work, but at the moment, I am excited about them!

I'm attaching some rooms I've saved. I have a lake house and I think the last one would look the best. The tan of it reminds me of sand. Very neutral and casual. Here is a link that might be useful: neutral grays and tan

Just ask the demo company how this came to be. Here's what I'll bet happened: the neighbor heard you were having the existing structure demolished. Neighbor was home when the demo company arrived and walked over to ask if they could have this piece and offered to pay cash for it to be shoved over on their property. OR, the neighbor is related to or friends with the demo company and actively pursued this with them without your knowledge. Maybe Joe the demo guy is a brother to Moe, your neighbor. OR, the demo company has a system in place whereby they notify interested parties when they will have a salvageable building available.

Didn't get your response on floor plan dimensions nor do we know if this is your furniture or perhaps furniture that came with the house or simply furniture on the listing documents. I'm taking a chance that it came with the house... Don't have a picture of the kitchen either. Paint, paint, paint! It's inexpensive and can make a huge difference. I would keep the white ceiling and walls, that part is very nice and continue what ever isn't painted in the same white colour to tie everything together. If it was for me, I would paint the exterior a charcoal grey with white door and trim. And, if you ever have the budget, I would extend the front deck to cover the width of the house + the right side since there seems to be a patio door there. It can be with or without a railing depending on the grounds. I would paint all the dining chairs in satin finish black and get off-white or light beige seat cushions (Ikea - Amazon $10-$12 ea.). I would also paint the table and bench base in satin finish black. You can possibly spraypaint all these items. Hard to see exactly what the coffee table looks like but if it doesn't fit you can also paint it black. Remove all window treatment and replace with white side drapes with black rods (Ikea curtains with grommets $50/pair - rods also inexpensive at Ikea). You can buy sets of pillow covers for the sofas (Amazon set of 5 for $37 (20x20 inner cushions $12 each in feather). I show an natural fibre area rug and front door mat but don't know the size since we don't have room dimensions so can't give an idea of price but it's nothing expensive. You can also buy a futon cover (shown in black) for $123 on Wayfair. Get a few prints, for good prices look on Amazon, Wayfair, and at Home Goods. For the bathroom, I would paint the walls and wainscoting part in white, and I show a white vanity, black framed mirror, sconce lighting (all from Home Depot) with peel & stick wall paper on 2 walls (not expensive on Amazon). I also show a white roman shade on the window. Hope you'll send dimensions so we can give suggestions on the floor plan.