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.
Michelin is the only tire I will buy. I have been using Michelin tires, specifically the LTX M/S for over 15 years. I put over a hundred thousand miles on one set on my CRV. I also have two Ford E-150 passenger vans and I have had one problem in all those years and Michelin customer service went above and beyond the call of duty solve it. It's the only tire I will ever use.