reliable car that is not expensive to repair, has a lot of interior room so you could sleep in the car comfortably

I too have a friend who has a Honda Element, and he loves it. A real outdoors guy who does in fact, sleep in his car on occasion. He likes the "flush out" interior that allows him to get rid of the mountain bike dirt etc.

You might also consider a Prius wagon. They are quite roomy as well. Reliability, of course, is excellent. One of the cars I own is a Lexus RX and it has an interior cargo space of 87 cubic feet with the seats folded down. I recently a full-size, tall water heater in with room to spare. Those are AWD and are extremely reliable.

The last suggestion that is rarely considered might be the Mazda MPV (van/suv) which has 4wd. The next iteration was the Mazda 5 minivan that seats 6 but doesn't really act or look like a minivan. It has a lot of interior space for its road footprint.

One other that has a surprising amount or room with its "fold flat" rear seats is the Honda Fit. I owned one recently (the latest) and came away very impressed with its fuel economy and front wheel drive traction. I did find the road noise intrusive. Its cargo space was cavernous.

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I'd also recommend the Prius V, but you said you wanted a car without much technology, so that's why I left it out. My 250,000 mile Prius is still going strong on its first hybrid battery. Electrical problems are inevitable in older Prii.

The Honda Fit might not have enough room length wise, although the inside is enormous.

If you're talking about sleeping ONE person, the Fit actually works great; I slept two weeks in mine at a campground over the summer - you have to flatten out the 2nd row seats, move the passengers seat all the way forward and put the back of the front seat flat. Then two couch cushions directly behind the passengers seat back makes for a 7' long sleeping space. And you can stash your stuff behind the drivers seat.

I'm a fan of the Element too, but they're kind of an in-demand vehicle, so you'll only be able to afford a super high milage one for $5k.

I agree with you that you might as well stay from the AWD vehicles since you don't particularly need that and the feature just adds repair cost and lowers MPG.

My thought is that if you need more space than the Fit, the Mazda 5 is the next logical step-up-in-size option (it's available in MT) and if you need something larger than that, you might as well bite the bullet and get a slushbox minivan (an old Toyota Sienna preferably).

Some great suggestions here. The tough part will be finding a good car without ultra-high miles for under $5k. The Honda CR-V tends to be very reliable, but once they're under $5k it's because they have so many years and/or miles that some repairs are likely. Probably a similar situation with the Element. The Fit is a less expensive car, so it should be easier to find a good one for $5k.

Common problems with the Mazda5 include suspension parts (not terribly expensive, especially if you can do the work yourself) and rust. I'd only consider one if you live where road salt is not used.