I struggled with a solution to get 4 people to sleep comfortably in a class B. I created sportsmobile floorplans and everything. The bottom line is "not unless you are willing to sacrifice something". The main problem you are going to have is storage and livability. Every morning and evening, you get to play, what I call, "the lego game" either putting everything in the mode to sleep or to use for dining. For me, it was only wife, 7 year old daughter and myself. The single bunk I used on the front 2 seats in my CS Adventurous. That alone was a pain in the butt. With 4 people, forget bedding, you are only going to be able to use sleeping bags and maybe pillows. Add in clothes and food and all your storage is full in the class B. Good luck being able to bring chairs, firewood, a grill, toys and stuff.
After my first season camping, I am going to add a travel trailer (RPod 182G) that will be dedicated for sleeping only. When I get up, I want to not have to put away my bedding and then covert the bed back to a dining table. I want to get up, make coffee and breakfast and be done. I feel that I would spend over an hour everyday playing this lego game and this ruined the RV experience.