1. All have the potential to become a money pit. Gas MPG is in the 14 range, under good conditions.
2. D1 have simpler design, less bells and whistles, and less capability in some situations.
3. Pre-inspection by mechanic is money well spent.
4. Would advise combustion gas in coolant test - a bottle of it from car parts store is like $50, will test a dozen or so trucks. Head gaskets are a popular problem.
5.
www.statewidelist.com will search all of craigslist for your state, you spec price ranges, owner or dealer, etc., it sorts by metro area. If you want to look for several things, it can do that as well, like "rover|jeep|volvo" (use the | separator, which is over the "\" symbol key).