How to use the same waypoints in several routes.
Basecamp has list folders and lists. Folders are collections of lists, and your data (routes, tracks, waypoints) are stored in lists. It's possible to store the same waypoint in different lists by using the copy function.
1) Find or create the waypoint that you use in more than one route. I have a list called "waypoints", and in this waypoints list there's a waypoint called "burdens home" - I start lots of routes from home.
2) If I want to start a new route to Wardy's House, I can create a new list folder called Route to Wardy's House, and in that create a list called Wardy's House Wardy's Fast Route
3) Back in my Waypoints list, I select Burdens Home and Wardy's House waypoints, right click, which brings up a menu. Select copy.
4) Go back to the list called Wardy's House fast Route, click in the box at the bottom, right click then paste.
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5) Select both waypoints, right click and select create route from waypoints. The route is created and then you can mess about with it.
Repeat as many times as you like, call the way points Start and Finish if you want (but this will get confusing). Create as many routes as you want but each route will have to have a different name.
Things to bear in mind - although the waypoint Burdens now seems to exist in 2 places, it 's really the same waypoint with a shortcut to it. If you change it (name, position etc) it will change in all the places it's used.
I don't know if this is the answer to your question, but it might be useful