If you'll be plugged into electric there's really no advantage. If you will be living in the TT full time I highly recommend being plugged into electric. If you intend to live in it full time and not be plugged in then solar panels will be almost a necessity and well worth the money. You'll need as many as you can fit.
If you just want to occasionally camp off the grid then a solar panel is worth it in my opinion. I don't like to have to listen to a generator (mine or anyone else's) when I'm camping.
I'd recommend at least a 100 watt panel as a minimum. Panels get cheaper on a watts/ dollars basis the larger you go. A 250 watt panel or larger, if you can fit it, would make the most economic sense.