Bring cash to the test drive and if you like it then strike a deal. We all know you have talked yourself into it, its now a matter of does it actually make sense.
Try out everything (AC, power windows, 4 wheel low, front and rear lockers, cruise control, sunroof, stereo, seats, wipers, etc..). Use a paper towel to check all of the fluids you can access (oil, transmission, power steering, brake, coolant).
Ask that you get a chance to start it "cold". Before turning the key verify the check engine light works and that it goes off once running. Save the locker and low range test for a gravel parking lot and after its been driven a bit.
If anything doesn't work use it to negotiate. Listen for wierd noises, drive it on the freeway and get an overall sense of how things feel. If this turns out not to be the "one" then at least you have driven an 80 to compare the next one to. Good luck!