We have a 35foot bumper pull with a 10foot garage. I fit 2 quads in it easily, but one is a little smaller, They are listed in my sig line. You need to measure out the space you will need by sitting your 2 atv's next to each other and see what type of footprint you have. Your length should be fine, mainly need to worry about the width of the 2 side by side going in the back door. You also still will have the bed of your truck as your kids get older for another ATV.
We use the Equalizer 4 way for our hitch, seems to work out fine. I have looked at the Hensley and pondered it, but I do not see a real reason to yet either.