There is some great coast just down from you... and your rib can do loads.
teignmouth and river Teign I'd give a miss, although as you come into the Teign on the Shaldon side there are a few pubs in walking distance, one about 100ft from river, but id probably give them a miss. The ones up the top of the estuary are very hard to time it.
maidencombe - café on the beach in the summer
Babbacombe - pub, but pier is private, so really need to drop anchor which is not great
Torquay harbour id recommend, moor up on the visitors pub for a few quid and loads around the harbour
Paignton - not so easy to stop in the harbour, id not bother
Brixham - easy to stop on pontoons, and explore town
Dartmouth - easy to stop on pontoons and explore town
Salcombe - easy to stop on pontoon and explore town
Just outside Salcombee there are a few beaches that have café's I think.
I used to use my 5m rib from Teignmouth and do all of these quite easily. It might cost a few quid to use a pontoon/taxi, but well worth it.
I suggest start at Torquay, as that easy, and the scenery from Teignmouth to Torquay is stunning. Then go for Dartmouth.