Wife and I are planning to full time for 3 years or more. We did this back in 1994 in a 40' American Eagle and had a great time. At that time we generally stayed in a park for several months moving from the north to the south following the weather patterns.
LT is not a tire rating but a category of tire. LT stands for light truck and as the name suggests, these tires are designed for trucks and SUVs. The label LT is usually placed in front of the tire size. The other common type of tire is a P tire.
The largest tire you can fit without a chance of problems on road is a 33x10 tire (also called a pizza cutter). An example is the 255/80/17 BFG KM2. Because this tire is the same width as most stock JK tires, there is no issue on road, despite the larger diameter.