I would suggest you ask the dealer to put water (full tank), fuel (half tank) and propane in it, then have them weigh it. That's your starting weight, from there you can evaluate if your truck will do it.
My 32' (34 foot including the tongue) which has no slide is 9,800 in that state and closer to 11.5k loaded with my toys and has a sticker max weight of 13k.
Full water because coming with empty black/grey or coming back with full black/grey that weight is still there.
Good luck with the shopping and decisions!