Actually you will get better milage with the diesel,more so since you are planning to wheel the jeep. you have to figure in size of tires adds alot of weight,and requires the engine to work harder to turn them.
With that being said if your set on the 2 to 5 k your best bet would be a yj.I'm not sure what years they ran,but they are the only wranglers with rectangle headlights. if you are lucky you may find an older tj around the 5k mark.
One thing is for certain do not get anything but a 4.0 liter, it will save a ton of heartache and problems.

out of all the jeeps in this town the d**n gremlin had to invade mine

I've done so much,with so little for so long i can practicly do anything with nothing