On an older class C we had I used one of those small solar panels to keep the chassis battery up while stored. Made little wire hooks to hold it flat against the drivers window so the low winter sun would hit it [this window faced south when parked].
On our current rig I have added a couple of 12 volt [cigar lighter] outlets connected through a fuse directly to the house batteries; the disconnect switch would not cut these outlets out of the circiut. You should be able to use something like this to plug your solar panel into, as long as the panel is in direct sunlight during most of the day, and is large enough to overcome the phantom loads your coach puts on the batteries.
I see you are in Yuma. My wife has cousins there that we will be visiting next month. Wishing you and your's Merry Christmas.
'97 Bounder, 32H, Chevy 454; ipd, Bilsteins, Air Lift, Banks, Hendersons, Solar.