you can't have an ideal boating place without mentioning a few places up here.
oban is brill (easdale rib rendezvous and corryvreckan).
loch lomond is a must see when you are up here, you pass it on way to Oban!
kyles of bute, epic scenery.
launching isn't an issue, plenty of slips around the place depending on where you are. everywhere above you can stop and go ashore for food etc.
some local vids i've taken through the years.
(from kip marina)
(bottom of Kyle of Bute and Portavadie round the corner, playing with the dolphin)