I have a 3year old son and a 4mo old son. the 3 year old has been camping with us in the camper for over 120 nights since he was born. We have been camping only 7 nights since the new baby boy came along but we have adjusted well and have plans for 60nights over the summer months. I would say you are definitely going to need a slide. Our old camper had no slide and we would never be able to make due without one with kids. Just being able to walk around each other inside the camper is pretty huge. I have the truck & camper in my sig but if i was doing that over again right now and could afford it i would buy the largest arctic fox camper they make and an F450 truck to haul the sob.
Biggest advantage to a camper over a trailer - u can tow something, (a boat or cargo trailer full of toys, just think dirtbikes, kids toys, etc etc..) I almost always tow a 14ft aluminum boat to the lakes i go to and inside the boat is full of the kids toys lol. I throw my dirtbike on the front of the truck, very soon my oldest son is going to be riding a dirtbike too but a 50cc bike can easily be tossed into my boat.
Almost all of the places i camp at are 20+ km down logging roads, trailers absolutely do not last with that kind of pounding every weekend, they fall apart.
Recently went camping with some friends who have a nice 30ft trailer. Wife and i were like wow this thing is massive inside. still would never trade it for the camper!
As for whats faster to get hooked up to your truck. Definitely a trailer, thats like 2-3min max.. I have loading the camper start to finish down to 15min.