I think a lot depends on the terrain you plan to cover. I can not see that cart working well if you had to go over logs, piles of debris, even street curbs, and ditches of any kind.

In Worldwalk, by Steven M. Newman, he lugged a backpack around the world, but when he reached Australia he used a two wheeled golf cart, to which bicycle wheels had been added. I think something like that might handle rough terrain better than a fourwheeler...