Well...I've done 11 Road Scholar tours, lol. AND 11 Rick Steves tours, more lol.
You may be hooked after you go on one so don't discount traveling again to Europe with either tour group. If you are traveling solo both groups welcome solo travelers and I've had wonderful times on all my trips. I do agree that if you want something more comprehensive, I'd go with the RS tour - Best of England being a bit more comprehensive than Villages of Southern England, although as mentioned it does not include Cornwall.
The international Road Scholar tours I've done are:
-Best of London (this was 2013 and they've changed this itinerary up a bit)
-Celtic Wales/Pembrokeshire and Carmarthenshire
-Walking Ancient Pathways and Iron Age forts in UK (this itinerary has changed as well)
-Brittany and Normandy
-The Art of Living in Provence
Currently signed up for (because up until 12/31 Road Scholar had a guarantee of a full refund of the deposit if you cancel 90 days out from travel)
-SW France (October 2021-I doubt this one is going to happen)
-UK Gardens and the Chelsea Garden Show (May 2022)
I've done 5 activity based programs in the US including Hiking, birding and genealogy.
The Rick tours I've done are:
-Heart of Italy
-Best of Ireland
-21 Day Best of Europe
-Best of Paris
-Best of England
-Paris and the Heart of France
-Villages of Southern England
-Best of Scotland
-Belgium and Holland
Because I've done a lot of Rick's comprehensive ones I now kind of choose either tour company based solely on the tour itinerary. I've often done back to back tours, sometimes 2 of Ricks, sometimes 2 of Road Scholar, sometimes one of each, lol. Now I usually add in a few weeks before and after as well. For ANY European tour I recommend arriving at least 1 night ahead, 2 is better, a week is even better, lol. This means you are not picked up at the airport by Road Scholar but it's pretty easy to get to most starting points and if you are unsure folks here on the forum can give specific information.
For Best of England I did time in London before, then took the train out to Bath several nights ahead of the tour as I knew there was a Jane Austen Festival happening and I wanted to attend some of those events plus see people walking around Bath in costume. So much fun!