I am a Patriot fan, but I agree with the others that anything over 150,000 is going to need work. If you want anything trouble-free, get something <100,000 miles. A lot depends on how well it was taken care of before you got it, and what you're paying for it.
Best case scenario, it runs like a charm with minimal problems. Worst case scenario, if you and your kid like working on cars, this could be a fun time!
My Dad & I had a great time fixing up my 1960 Ford Falcon when it was just a 10 year old rust-bucket. It was a learning experience and a bonding time. Dad had a lot of mechanical experience and that car had its share of problems. When I got it free from my uncle it was worth the price. It had just had the engine rebuilt but everything else was poised to go south. The clutch was a rolling disaster I learned to cope with, and I had the brakes done professionally, then I replaced a bunch of stuff on it myself that first year -- nothing major just belts, hoses, shocks, generator, radiator, starter, battery & cables, and a whole lot of body work. I did my own oil, learned to use a grease gun, and in those days plugs were 10,000 mile items. Cars were a lot easier to work on back then.
So your question is a good one and it seems like you know what you're getting into. My present Patriot has 120,000 on it with nary a problem; my 2008 Patriot got almost to 300,000 with very little EXCEPT the tranny failed twice, but both were covered under warranty. I sold it to a friend a year ago and my Wife saw his son driving it today. :smiley_thumbs_up: