In my opinion it's really nice to have beds for everybody so you don't have to fiddle with the dinette or sofa every night and morning, which gets old quickly. There are actually some fifth wheel models that have a mid-bunk setup with a rear living area that would give you both features, but I'm not aware of any that would be close in size to what you could pull with your truck.
In your situation I'd go for a bunkhouse and then plan on setting up some comfortable chairs out under the awning to sit in while you drink your coffee. You could even add an extra awning to the back of the trailer if you really wanted to sit out on the back end of it under cover.
Just my two cents, but there's a reason bunkhouse models are popular with families.
