Brunell was into a good thing showing a "Riflesideholder," which might be muy appropriate for Neuvo Mejico. You might want to do a merge of these two approaches. Thanks to both of you for the ideas. I'm off to China tomorrow, where the path is all steps out of hewn stone. No carts for me, alas, it'll be backpack 'til I puke.
I've been using a Baby Jogger for years with my 4 x 5 equipment. I can carry everything I need. It works weel over level terrain and and I've managed over moderately hilly terrain with some difficulty.
At one point I ordered a Sherpa cart, but when it arrived I found it was much too heavy for me to handle with my bad back. There were also other problems, so I returned it.
A few years ago I put a salvaged backpack frame on a cheap golf bag cart with hose clamps. I then slung my LowePro super trecker on it and draged along. Works great in an urban setting and groomed trails too. Folds up to stow and cost <$50 and Looks, well . . . ."manly".
There are only three types of mounting flanges; too big, too small and wrong thread!
My sojourns are more urban in terrain, but for you trail walkers, this might be useful: