We originally had a 2012 36RL, very similar floor plan and loaded for long term travel we were at 17K with just under 4K on the pin.
There are only a few Redwoods that can be towed by a 350/3500 SRW and be under the weight limits, most really require a Dually is you wish to remain within all weight limits.
Our current 39MB had a brochure weight listed as 14K but left the Factory at just a tad under 16K empty.
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