Is there a way to show more than one region at once? at least with the OSM updates anyway?
I do not believe there is a way to load more than one map onto Basecamp, at least when I looked at it a couple of years ago. This is mainly because the file name must be a specific, therefore cannot be duplicated.
What is your preference for using Basecamp versus some of the online mapping tools such as Ride with GPS
, or Garmin Connect
Aside from fast, responsive, & friendly user interface, Ride with GPS allows for choosing among many available maps: Google, OSM, OSM bicycle, OSM outdoor, satellite, topo, etc.
Strava, on the other hand, allows you to choose routes base on heat maps that show most popular & used routes.