We have a bunkhouse, Sundance 3100RB, which we like. I like the half bath for the kid but the door to the outside is a mixed blessing. It's nice the kid/grandbabies can go the bathroom without running through the camper but when they get older, it'll be easier to try and escape or "slip out the back". A second door is a nice emergency exit. Having their own room is great for putting them to bed or for them to play on a rainy day.
They no longer offer my model but the
SD 3400 QB is similar. Something like the
SD 3300 CK which does not have the half bath might also be an option.
Pin weight is going to be the issue with your truck. The pre 2005 trucks were limited on cargo capacity and 5er's average a 25% of loaded pin weight. A 12,000# loaded trailer is around 2,500# of pin weight in the bed of your pickup.