Sorry to hear about your back Chris!!! No fun!!!
I use my bass buggy all the time, habitually driving the Alcoa/buggy forward of me, either in or out of the bass bag, usually mostly on my right side with the Alcoa neck pressed against my right shoulder and right side of my neck, so that I can assist it with my usually free left hand as needed. Lifting one wheel on either side of the buggy provides a mechanism for strong turning the opposite direction. But lifting one side is not practical if you're pulling or carrying something else with the off-hand, so a person has to learn to drive very deliberately. To be clear, steering the bass buggy in front can be squirrely. very much like pushing a one-handled wheelbarrow.
I have read of people here in TB/DB pulling their double basses on their buggies... I haven't been able to manage that well yet, mostly because I'm afraid I'll clip a person some unknown object with my Alcoa's bridge (or bridge bump when in the bag) and cause some sort of setup havoc; I guess I'd rather see what I'm hitting so I know what to expect when I try to play.
I haven't tried endpin wheels, and probably won't because I'm using the old original wooden endpin and endpin plug on my Alcoa, which has no wing screw for tightening. That old endpin plug is cracked (but currently still functional), so I will eventually replace the old assembly with a modern endpin assembly, and when I do I may look into various endpin wheels.
I just got back from a bluegrass event cruise early this month using the Bass Buggy. My wife and I had all three of our main playing fretted instruments in a good size Coleman folding wagon along with some foilding chairs, stands and miscellaneous small bags, two good size wheeled suitcases and the Alcoa on the buggy. I'm sure we looked like some sort of variety show on parade.
I hadn't intended it to happen this way, but on this cruise, basically my wife and I each had two wheeled contraptions to move at various times. I was in charge of the Alcoa, with my left hand, and another randomly chosen item with my right hand, and I hadn't one-handed or left-handned the Alcoa for long distances on the buggy before, so the cruise was an interesting testing situation for it.
I found that with a little thinking ahead it was very manageable, even getting in and out of crowded elevators, or traversing the ship on deck where other people would be coming from various directions. Having the Alcoa ahead of me sort of broke the wind as far as oncoming crowds were concerned, often with the other item trailing behind me in my wake. I did find that my Alcoa/buggy arm became tired with some of the longer stretches of walking on the ship, and I learned to switch from one arm to the other pretty smoothly.
While THE BASS BUGGY IS DEFINITELY NOT RECOMMENDED FOR USE AS A STAND, its balance points are handy for times when I'm standing next to my Alcoa and lightly holding it. I found myself doing that a number of times, especially when stopped to talk with random passengers about this "huge aluminum cello" or "funny looking bassoon" that I was transporting from one end of the ship to the other.