I'm curious why you feel you don't have room under the curbside bed? How different is it from my 2010 2551 pictured above? Did you unscrew the platform so you can see all the room that is under there? The power comes in from the rear of the coach and there is plenty of wire to work with. That cable is heavy gauge wire and not that friendly to work with in tight quarters. I chose that location because others recommended it. Your choice of course.
Dougn
My 2015 model 2551 has almost no room under the passenger side. I had difficulty adding a cell phone booster that's maybe 2" thick by 6" x 4"
Yes, a lot of space is taken up by the furnace duct work. But then there is the fresh water tank, the inverter (with associated thick 12v wiring, the furnace, the power distribution panel & charger, several relays and the water pump.
It's pretty tight in there. And in the 5 years since mine was built and what's being built today... It's probably gotten tighter.