4wd for sure...
Last summer I was pulling my TT down a small road to a COE camp ground. I had to pull into the grass to get past another trailer. The grass was wet, ground was FLAT. When I went to pull off rear wheels slipped, no traction. Turned on 4wd high, gave it gas and boom, took right off with no slippage. I would be sure to get 4wd, you never know when you might need it, gravel, wet ground, mud...