One thing that I have never quite got right in my mind (with my mind that is easy) is why is there such a large desolate strip on these borders. Does the road just end short of the border on both sides? Were there enough "wars" between the various 'Stans" after the demise of the USSR that relations are still very frosty? Or is it some sort of leftover from the Soviet days?Re dragging bags around. We were warned by the trip notes that there would be one border crossing that would involve a long walk through a 'neutral zone', and it may be hot at the same time.
The long walk came to pass (about a km), but it wasn't hot, although it could have been. Fortunately in this case the surface was pretty smooth. All border crossings involved some walking across neutral zones, and nearly always this involved some rough and uneven surfaces (as in multi-patched bitumen-paved surfaces, potholes, cracks, gutters, cobbles etc) and some steps (up and down into checkpoint buildings). A couple of times we had to contend with stretches of gravel.
The lady I helped a couple of times had a four-wheeler, which I definitely wouldn't recommend and it was pretty heavy. No-one else had this combination and I don't think there was much drama elsewhere. Its a group of 16 and someone will always help.
I had a large, heavy bag AND a carry-on sized bag
Re being on your own occasionally. On the transport, except for a couple of days in the 4WDs, you'll always be able to sit by yourself - there are plenty of spare seats. All of the 'singles', and occasionally the couples did this on this tour. But at lunches, and many dinners, its a group thing. Many dinners are 'do your own thing' though and I know John and I sometimes skipped lunch to wander about either by ourselves or separately. And you can get a single room of course. After a couple of days, everyone got to know each other and if at that point you said 'I may not be sociable today', I reckon people will understand. Like I said, the participants are mainly experienced group travelers and will know what you are about.