My last reply w/photos to this thread got erased by the server so I will try again.
I mounted my 2 panels on the front shell of our 3124 using Liquid Nails (recommended by RV Solar Electric) to attach the 4" wide 1/8" aluminum stock to the roof of the TM. The panels are attached with pop rivets to the aluminum stock.
Our 3124 is an older model and the AC is mounted above the bed so avoiding it is not a problem.
I ran the wiring down the right front of the upper shell and across the bottom to the half way point where it heads out to the controller mounted on the inside of the V just before the hitch. When the shell is up the feed wire heads almost straight down to the controller and when the shell is down the wire nestles between the propane tanks.\
From the controller the power goes to a custom battery tray I had made that fits between the frame just behind the propane tanks. From there the power heads to the battery inside the kitchen cabinet although now I only use 2 batteries, one in the tray and one inside the TM. I have found that 2 Lifeline gel batteries supply all the power we need.
I prefer not to have a control panel read out in the TM. I just use the TM's battery gauge or a multi meter to see what the charge is.
Nothing fancy, but it has worked well for 13 years.