After finishing all the buildings, it would be nice to have something to use all the stones on. I would like to suggest new Outpost technologies of Paved Roads, where you could use a lot of stones (and some other resources) to pave the road to each of the caravan cities. After the road to a city is paved, bad weather would not prevent the caravan to go to that city (without increasing the bad weather probability for the remainkng cities). Maybe paved roads would reduce the traveling time a bit too?