3 boys, your going to need space to haul bikes and other toys that they will deem necessary as they grow. A bunkhouse TT will allow you to add a topper to the truck for their equipment. A small 5er toy hauler could handle more stuff and convert into their bunk/personal space at the campground.
Seems you need to pick a unit type first then try to match the TV. My gasser has a tow rating around 13,500 for a 5er not sure but in the 10k area for a TT. You need the lower rear ends (4.10) for more capacity. Of course the dallies have higher payloads. I can't speak to your commercial requirments, thank God here I don't have that problem.
You better watch out, I see you at the bottom of a 3 boy pile up in the near future.