I did most of the work myself - installed all the TL tiedowns, etc. The dealer installed the bed plug - charged me 1 hour of labor and the part. So not horrible. I also just installed the big wig front and rear sway bars, myself - although it took me a little longer than most people probably do.
DB, those are the manual disconnects for the Solar panels - since this is a used unit, the guy before me installed solar and put these in so he could disconnect the panels or batteries at any point by just flipping a switch. He also installed this solar controller and the fuses. Not sure I'll ever use them, but I suppose in a bad situation it would be good to quickly do it.