We were out for 37 nights this year - From May 1st to mid-October.
We used electric heaters (with LPG furnace to supplement) for the cooler weather; fridge on LPG for travel, electric on site; cooked with LPG.
Used half of one 20 pounder, didn't touch the other.
We do run our BBQ off a separate 20# - we went through about 1 1/2 tanks on it this season...
2014 Grey Wolf 28BH, behind a 2015 F350 Diesel Crew Cab
Nights Camped 2015: 37
Nights Booked 2016: 44
Nights Camped 2016: 41