I'm assuming the 31SL is similar to other Redwoods in the front section. I have 2 150 watt panels on my roof and arranged them so that I could easily add 2 (or possibly 4) more panels down the road if needed.
As for running wires. My wires start on the roof right above the forward/center light in the bedroom. From there they run in the ceiling through a hole in the metal roof joist and exit into the closet right by the closet light on the ceiling. From there they run inside the closet, to the passenger (right) side of the RV, down that wall (inside the closet still) and to the bottom. Then they run through the closet wall into the bedroom (going towards the rear) and are underneath the cabinets space until right above the Propane storage area. I then punched a hole in the passenger side propane storage area to run them into, which easily routes them into the battery compartment from there. Once completed seal the crap out of all holes so that no air (or propane) can get through.
I bought all my gear through AM Solar (http://amsolar.com/
) as they both know Solar and know RV's. They also have the best roof box I've seen for connecting solar panels to current wire. Be sure to follow the 2% rule if you can when sizing the wire. Measure the run for the wires, add in how much max output your panels have and size for 2% loss. If you think you might want to add more panels later, make the wire the appropriate size as rerunning wires is a major PITA in an RV.
Lastly, oversize your charge controller. I have a 30A MPPT and I can tell you that with just (2) 150 watt panels I'm close to maxing this thing out when I'm south and the sun is high. Also be sure to have ample battery capacity so that you capture all the energy you can for night time.