I have 4, 100W solar panels on my 2720SL.
I have 2, 100W panels on the rear shell (wired in series) and 2, 100W panels on the front shell (wired in series). I ran some 10G MC4 cable from the front shell to the rear shell panels and attached them in parallel. This gives me about 11A @ 35V to my MPPT charge controller (in full Sun) and the charge controller converts that to about 20A @ 19V to my 230AH LiFeP04 battery.
The solar wires from the front to back fold under the front shell, on top of the rear shell, when the trailer is folded down. The solar panels are mounted to the roof with 3M VHB tape. No holes in the roof.
https://www.amazon.com/CS-Hyde-Confo...04V40K92&psc=1
I only have to run our generator if I want to run the A/C or if it is a cloudy day. Otherwise, we are totally self-sufficient. We even have a 110V, 4,5cu ft dorm fridge instead of propane fridge.
We put our charge controller on the back of the lower shell, under the bed slide out, where it is protected from the weather and very close to the batteries.