Thanks to folks who helped with local knowledge.
It was too hot to be at all ambitious....
As planned, first day I took the ferry from Oban to Lismore and rode South. This time I found the correct track to the very south west - Port an Rubha, just across from the lighthouse - which was beautiful and deserted. It was very hot, so I just pottered about looking at archeology sites, then back to the village shop for water. On to the Heritage Centre for lunch, and surprised to see about 20 bikes of all types parked outside. I knew that a bike hire business had opened at the north of Lismore, and now a lot of folks come over on the foot ferry from Appin, hire a bike and get as far as the Heritage Centre and back - about 6 miles in all! The food was very good - interesting options for special diets/fussy eaters and all prepared to order by two chefs. Three or more serving staff, so also very quick even though this was a sunny Bank Holiday Saturday. Indoor and terrace seating, bikes in view, highly recommended.
Having looked round the museum, and chatted to staff/volunteers, I decided there was enough history/archeology to keep me interested if I came back the next day. There have been archeological digs the last few years, with some exciting results.
So that's what I did. Rode to the North ferry point then dawdled back checking out all the side roads, brochs, cathedral site etc.
So a low stress, low mileage couple of days which was just what I needed.
Hope to do the Oban - Lismore - Appin - Connel loop another time.
Thanks again.