"How do they deal with flex between the camper and the cab?"
I've never had the opportunity (or desire) to try any extreme 4wd trails in my Tiger....off the pavement I've stayed on pretty decent forest service dirt roads and then driven somewhat off them to get to my campsites, and I haven't had any issues with that use. But I can't give you any first hand experience with driving on severely uneven, rutted or eroded trails to answer your question.
My Tiger has handled washboard roads fine, and driving rather slowly and cautiously, it's handled dirt trails up in the Sawtooths and the Mogollon Rim country fine too.
I think these are well constructed rigs but I don't think they're really designed for hardcore off-roading.
My previous 2wd 21' class B+ camper van was a complete misery to drive on any dirt or gravel roads, so I'm very happy with the new backroads areas opened up to me with the Tiger, but I sure wouldn't think about driving it on some of the rougher trails that I take my K2500 HD Chevy on!
If you're really curious about this issue, PM me and I'll post an inquiry on the Tiger's Owner Forum and get back to you with the responses.
