For the weight, wonder if you might be able to do better than 1/8" steel? Maybe some type of ballistic composite laid over a lighter shell? Have you done the math? Am honestly just kinda curious, how much might all that 1/8" plate might end up weighing? Almost went the route you did, but decided to build an M109, primarily because of the size/weight. Wanted to be able to get pretty far off the beaten path and decided against a 5-ton once I figured out that I couldn't even change a tire by myself. But sounds like the places where you're planning on traveling are made for big logging trucks, so can see how that makes sense for you. Cool project.