I built a 4x 7 custom trailer with a rack system that I can strap 4 bottles of air in standing up. We took this trailer north when we dove in Lake Superior this past summer. We put about 800 miles on it round trip and it hauled like a dream. The trailer is an open design with a custom tarp that snaps down over the top of it. I managed to hall 4 tanks, two sets of dive gear, two big coolers full of food and beverages, 3 mountain bikes, an 8 man tent, 3 sleeping bags, 3 cots, 3 duffles full of clothes, lawn chairs, a grill, a dog cage, a lantern, dog food and toys.
This trailer is pulled behind my 95 Pontiac Grand Prix. Great gas milage and I was able to drop[ the trailer at the camp ground when not in use. On dive days we loaded 4 divers gear in the trailer including 8 cylanders and an OMS HID dive light and still had room for a couple of additional sets of gear.
The trip included my wife, son and my 90 pound labrador in the car for the trip there and back. The trailer is great because I can pull up to the waters edge and step in the trailer to don and doff gear. I will be adding some addditional goodies this year including a bike rack and a locking cover of some type so that I could store gear in the trailer when I am not in site of the vehicle like at a lunch stop.
Mitten Diver