For the people mover side of what you need, you already have the right vehicle. It pulls your existing trailer, maybe not effortlessly but certainly adequately. I would stay where your at until you are getting closer to finalizing what a fifth wheel would look like for you. With a 2017 Tahoe, it would likely make you financially feel better if you got more miles out of it anyway. The new HD gas engines from GM and Ford will have some time to sort themselves out as well, which would be another bonus. Buying a tow vehicle now for trailer way out on the horizon, could result in underbuying or overbuying if your plans change again which they often do. If you are anxious to buy something now, then you would be best to go big so you don't run the risk of underbuying which is more expensive than overbuying. So in that case it would be 3500 HD Diesel SRW.