Unless there is a lot of traffic it seems unlikely you will find a two lane wagon trail - especially in a forest. I'm not sure what the etiquette was, but I suspect it was just a matter of finding a break between the trees (the historical equivalent to a wide spot in the road) to pull over and wait. Even today many roads in more remote areas cannot easily accept two cars side-by-side, one or the other finds a wide spot where they're not going to get bogged or go over the edge, and waits for the other to pass. (In wagons days they probably both stopped, totally blocking the track, and boiled the billy while they had a chat.
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