The most notable stops on the return were in Lithuania: the Hill of Crosses, Trakai, and Grutas Park. All of which were very worth visiting.
If you're interested you can research these places online. But I do have a couple of notes for other Overlanders:
You can stay overnight in the official parking lot of the Hill of Crosses for no extra expense other than the day parking cost. It's cheap and quiet!
We read about break-ins of motorhomes in Trakai, and we saw broken glass in parking lots so it's a good time to use the campsite, from there it's a nice cycle into see the sights. (Or you could take the water taxi over the lake).
I'll have to upload some pictures when I have a better internet connection.