I don't see how to fix that.  Ride is a container that includes the ride plan, right?  Looks like the ride already has a (possibly null) ride plan.  Is there a way for me as user to delete that ride plan and then add this plan back to it?  Or I could export/import GPX.

You can associate it with your ride plan by clicking the "Ride This Plan" button above and adding it to your ride but it won't show up as the default one, but I can fix that for you. This is a scenario I had not considered, wanting to replacing one ride plan with another for a ride. I'll add that feature to my list of things to do.

If I click on "Ride This Plan" I get this error...
"An error has occurred.Permission denied. (ERROR 31126580)"

Ugh. Sorry. Dump is as GPX and upload it will be the fastest way. You'll have to re-add the points of interest. I'm on the verge of installing all the new stuff but I'm going to hold off until after our ride so that I don't screw up the ride, just in case there are showstopper bugs during the upgrade.