It sounds like your current truck works fine other than 4x4? Too bad, the Titan sounds like it is up to the task other than that. If it came with a locking type diff and you went to more aggressive tires it might be just fine.
I would personally go with Option 2. In fact looking to buy my 3rd Cummins P/U now. Have always liked the easy power the Cummins truck delivers right off idle. The trailer and camper would be an easy tow with plenty of power on tap if you ever go to a bigger trailer.
I'm sure any of these trucks would work fine for what you describe above though.