Very sad to hear about your mobility problems, especially coming on top of having your kit nicked. Life's a bugger at times, and I marvel that some people seem to cop more than their fair share of bad luck than others. But then there are some in worse states, I suppose. Perhaps we only notice really bad luck when it touches those close to us.
The Kardan is certainly lighter than many LF cameras. I have one, a so-call JBL (Jubilee) model. It's currently my only 4x5 camera and is lovely for all its movements and Linhof precision. But there is more to it than just the camera, as you'd know, of course. I was only thinking the other day when sorting out my office after the move, that the kit that goes with the Kardan, lenses, holders etc, and the bag, all mount up to a lot of weight. I'd just come back from a walk near our new abode, to a railway bridge spanning the Werribee River, and was reflecting on how my mobility was deteriorating -- and I was only carrying 35mm!!! But I found it very difficult and dangerous going on slopes, and wondered how on earth I'd manage the 4x5 under those conditions. I'm toying with the idea of modifying a golf buggy for carrying 4x5, and only sticking to beaten tracks in future.
Sadly age catches up with all of us eventually, and it may not be long before I have to consider 6x6. Then 35mm... then point & shoot digital. The scenario could be depressing if we allowed it to get on top of us, but it won't because for those of us who love creating photographic images, it's the image that's all important, and the gear and processes are just the means to that end (as much as we delight in them). I know that's what has always driven you, Walter, and I can't see your spirit being crushed by minor irritations like these.
Looking forward to seeing your recent Mamiya images.