I've ridden across Siberia, here was my equipment list: Amsterdam to Vladivostok » Equipment

A few things to realize is that the gaps between services on the main roads are not as big as you might expect. For example, longest gap in water was perhaps 100 miles and less if we'd filtered. So it was useful to carry a 10L water bag, but typically only fill up in village and then go 10km out of town to camp. Same thing on food. It is a continental climate, so in summer at least the warm clothes are no greater deal than elsewhere. I did carry some more spare equipment, though the larger towns like Novosibirsk, Omsk, Irkutsk, Chita all had bike shops with pretty much what you'd expect here - and some smaller likely did as well.

In terms of being remote, northern Australia had larger gaps - from what I've seen western China as well. However, in both places if one was on the primary road, there was enough traffic that if one got into serious difficulties it would be possible to get a lift to a town.