We’re just back from a week on the Dart and cant recommend it highly enough (as I think I’ve said on the forum before, I grew up and learnt to sail in Torbay / The Dart so it is really a case of going back home for me). Plenty of launching options – Totnes, Stoke Gabriel, Galmpton, Dittisham, Dartmouth (higher ferry slip), Kingswear public slip – most of which have some degree of tidal restrictions. We chose Galmpton and then headed down river to Noss Marina where we left the boat for the week. Lots to explore on the river as far up as Totnes, plus out to sea – Start Bay to the south and Berry Head /Torbay to the north.
I would also recommend Salcombe either up the estuary as far as Kingsbridge or out to sea.
Plymouth Sound would also be an excellent choice. I’ve done a lot of big boat sailing out of Plymouth Yacht Haven (not yet sailed the wayfarer there, but will do at some point) and the facilities at Mountbatten do look good – you have to walk right past them to get from PYH to the pub!
This thread may be of help if you’ve not seen it already –