I rarely ever travel the "prevailing speed limit". It is usually faster than I am comfortable with while towing.
I have found that if I don't know an area, traveling the posted speed limit is usually okay for most conditions. This is when I don't know the intersections, corners, etc. This doesn't always work - we were visiting friends in Pennsylvania farm country, and the tight / narrow roads combined with 6-8 foot high corn growing almost to the edge of the road (basically completely blocking sight lines at intersections) made me slow down substantially.
If I am holding up traffic, I certainly will pull over when able to let vehicles by.