As I recall Julian's paper a consideration of the mechanics of transport was very much secondary and a bit of a "filler" as the main project was erection. I wasn't convinced by his musings about a formal track being built - it strikes me the labour cost would be massive, equivalent to building a 21 mile wooden road from Avebury all the way to Salisbury Plain and if there was any viable alternative they'd have gone for it.

Foamhenge strengthened this feeling. It revealed you just don't need a track or rollers to shift stones. I also think the "steering problem" is overplayed - and in fact it's actually created by the use of a track or rollers. In the absence of those, going off-line isn't a crucial issue and you can re-adjust the alignment periodically using levers or by the even more blindingly simple expedient of simply carrying on pulling but slightly to one side.