I would like to add some waypoints to a multi-day track to show the ends of each day section. I have tried with gpsies and bikehike but can't see how to do it. Anyone have any suggestions?
Bikehike calls them coursepoints.
Load a route. Then click on "Add coursepoint". Now click on the route where you want it to appear. In the dialog box choose "Generic" and give your point a unique name, so something like "day-1-end".
The other option in bikehike is that you can split a route into sections so that you have each day's ride as one GPX file. It's a bit fiddly if you have more than a couple of days. Choose "Cut to End" then click on the route where you want the new file to stop. This will remove everything "after" that point. You'll have to keep reloading the file and manipulating things to get what you want - there's a "reverse route" option that's handy.
I use Ridewithgps for this, "Add/Remove control point" then export as gpx route. I did this a bit on Audax rides so I knew where the next control point was. Doesnt work on Wahoo Elemnt though!