Make sure the Dealer adds the second battery and see if you can get two good batteries, group 27s or 29s, not the elcheapo no name 24 that has come in some. If you ordered the G rated tires (sure hope you did with a BR) make sure the pressure is where it belongs, our RL arrived with only 80 PSI in them. You might want the Dealer to put grease in the wet bolts, Lippert isn't installing them correctly and some won't take grease because the grease holes are not positioned correctly.
Good luck and enjoy.
Michelle & Ann
2018 Chevy 3500HD Crew Cab High Country DRW, D/A, 2016 RW39MB, Dual ACs, Auto Level, Auto Sat Dish, Stack W/D, King Sleep #, 17.5" Sailuns w/Disc, MORryde IS & Pin, Comfort Ride Hitch, 5.5 Onan, Res Fridge & Induction Cook Top