We are looking to buy a house that has obvious foundation settling. Exterior doors and some interior doors are 2 to 3 inches out of square. This house has an unfinished basement and I can't seem to find any serious cracks in the floor or walls. The house was built in 1961 and is in central Wyoming. This is going to be a fixer upper for us and I don't want to bite off more than I can chew. Being 46 years old does a guy just go in and resquare door frames? Or is this more serious than I am thinking?
Thanks for any help!

If, and I say, IF, the foundation is not settling as you have stated, the walls are doing just that.

A home inspection service will find the problem, that is their job, inspecting for possible errors in building maintenance and defects in workmanship. Get a certified inspector.

If it is found to be the walls/base plate, which is rotted, you can lift the house, this is not only tricky, but dangerous for the novice.NOT impossible.

By lifting walls(which will crack all plaster/drywall,that has been put in place since the settling has occurred)you can bring the home back to a respectable level,enough to keep the doorways even,if it was even when it was built.

More serious? The inspector will let you know this.

Ken