I solved this problem by using a TAD gear (replica) backpack that fit everything but my rifle and armor in. That way I make 1 trip to my car with all my shit in hands. Once on the field, I gear up and use the same bag to carry my stuff on the field. The only thing I still need is a hard rifle case to transport the larger weapons to the car. Everything else is not dead weight.
I can also carry my rifle on the backpack, or a helmet.