Assuming there are no broken or seriously warped joists or sills, the house would have to be jacked up high enough to build either piers or a full foundation beneath. Then there would likely have to be more very gradual jacking of the floor joists to try and restore them to a level plane. What effect this would have on walls, ceilings, etc. is impossible to foretell with any accuracy. This would be a time consuming and expensive project worth it only if the house itself is a)cheap enough and b)has some intrinsic value.

I'm getting an estimate this afternoon, to fix it various ways. Thinking that I can build perimeter foundation walls myself if I can get all of the piers to correct height.

Realtor calls this a "Little House on the Prairie" style house, full length front porch and roof like they do on log cabins. Floor plan is old-timey, with doors between every adjacent room. Of course, no central heat or air, little bathroom, old wiring and windows, likely no insulation in the walls. Great piece of land with mature shrubs and fruit trees, etc. It is pretty cheap, no one bought it when the government had their subsidy program going.

It may be too late for this, but I'd recommend getting three estimates on anything this complicated. Be realistic with what you can do yourself and how much money you want to sink into this project.

If the land is nice and the house is affordable, it may be a great deal, but I'd talk to some contractors with good recommendations....then make an informed decision. Some will let you do a good bit of the work to save on cost.