Hire an architect. Work out your solution with them. There are more factors involved in your solution than you think. Only someone that can walk both sites can properly advise you correctly.

None of that falls into the budget build category. If budget is important to you, conventional builder homes on flat lots are where you start. Unconventional of any variety always results in added costs. If the tract build budget pushes the envelope for affordability for you? Trying for something double that cost needs to get reigned in hard right now. It is not realistic.

Establish your bottom budget benchmark by looking at existing tract builds. Everything on your list ups the price from there. You are a much better candidate to purchase an existing split level and renovate it. That will be significantly cheaper than a new build as you can contribute sweat equity and maintenance.

There really just isnt big tract build subdivisions in my area. This is a smaller town that we are trying to build in. looking about an hour away, yes there's tract homes within our budget that have the needed square footage. Besides that, i really dont think its a good comparison. The price on a tract home isnt factoring in all the work ill be putting into this house.

I mentioned in the other thread, ive looked pretty thoroughly for homes that could work for us in this area and there just arent any. They are either too big, too small, or just cant be split the way we want.

As for the sweat equity, yes i could do some of the work like adding kitchen cabinets in an existing bi level. My expertise is mostly cabinets, door building, door hanging, trim, tile, flooring, sheet rock, things like that. Im not a roofer, electrician, plumber, hvac specialist, septic specialist, well specialist. I honestly feel that my sweat equity can be much better taken advantage of in a new build where all the things i can do are needed, and all the things i cant do will be brand new and not possibly needing maintenance in the near future. An older existing house is more likely to need work in areas where my skills wont do much good.

As for the sloping lots, thats just whats available at lower cost. For a nice flat lot, price jumps up another 30k or so. there just isnt much available in the area. My builder is the one that suggested a walkout basement could be an efficient way to get the space we need for lower cost. A sloped lot allows for a basement with plenty of light, perfectly livable, and 1 floor above. On a flat lot, you would still need 4 feet of crawl space, then 2 floors above it. With sloped and walkout, your adding another 4 feet of foundation, pouring a slab, and eliminating a whole floor.

This second layout with fill is obviously not as efficient as the dug down walkout, and also definitely to the point of more expensive than building on a flat lot. The question is, how much more expensive? Just very rough estimate. Would it be cheaper to spend an extra 30k for a flat lot?

As for classifying it as a "budget build", lets change that to building on whats available with budget in mind. Even if we end up building on a lot that has a not so budget excavation and foundation, im still going to do what i can to reduce cost where possible. Cadet heaters, laminate flooring, vinyl siding, etc.

Another thing, ive been talking with bank and the budget could possibly be up closer to 300k.

As for the sloping lots, thats just whats available at lower cost. For a nice flat lot, price jumps up another 30k or so.

The problem is what you'll save on the lot fees, you'll be spending to create a house that works on that less than ideal lot. There's a reason lots like that cost less. It's because in the long run, they cost more to build on so it's a wash.

As your mother gets older, will she be able to navigate the steps down to a walkout basement to get to her apartment? If the steps are outside, will she have to deal with ice/snow covered steps? Or will you have a driveway cut in, so that she can drive to the lower level of the house? This would add quite a bit of cost.

"No one here can really give you a definitive answer."

Fact worth repeating.