I have an 04 Liberty Sport with the 3.7L v6. Highway mileage of 20mpg at 65 mph. Best used as a versatile carryall with off-road capability and ability to navigate snowy roads confidently. Heavy body, which makes the 3.7 less of a monster than it should be. Not the greatest highway acceleration. There are some weak points - door window regulators are crap, and the hood and lift glass will probably need new cylinders. Body rust will probably be starting, even with an AZ vehicle. Good news is that you should be able to find a lot of parts in decent shape at your local junkyard.
I inherited my mothers 04 Libby with just 75k miles on it, for its first 14 yrs was in AZ before I drove it back to Chicago. I think its pretty easy to work on, have replaced window regulators, water pump & thermostat. Plastic impeller blade on water pump broke, I was lucky to find all broken bits before they circulated elsewhere. Plastic fender and bumper covers come off easily, allowing for easy replacement. The vehicle is tough - I got rear-ended & pushed into a step van with a solid steel bumper. The little sedan that hit me had airbags deploy (mine did not) and its front end looked horrible, it had to be towed. My front end suffered a bit, with front frame cross-piece bent in a bit. Spare tire carrier on swing-gate got pushed into the door about 1/2. I drove home. Repairs at Gerber would cost $3500 with biggest portion going to body work on rear swing-gate. I let Ins co total the vehicle, took their check for $3,500.