Bruce where are you going to be based? this will make a big difference to where you go. From Banff/Macduff to Inverness by road is 70ish miles so by boat alot of coast.
Others have covered ports up to Pennan/Gardenstown, next is Macduff which is a commercial harbour fuel a short walk 10 mins and food directly across the road from harbour.
Banff is across the bay crap access but nice town.
Whitehills is approx 3 miles further west small marina with visitor pontoon, showers etc.
Portsoy is the next harbour, tidal but you can slowly make your way in at low water springs. Very nice little cafe just of main street, shop and chemist.
Sandend is next small bad access and no facilities.
Cullen dries (most of the time even at high water)
Portknockie access with care at all states of tide, shop, pubs, chippy.
Findochty access with care all states of tide, shop, pub on harbour front.
Lossie across the bay from buckie approx 6 miles
Hopeman dries don't know haven't been for years
Burghead commercial harbour some facilities
Findhorn watch for the bar (contact Simon at the marina) pubs, shop and marina
Nairn marina but limited access and very shallow and flat long way out.
You can cross from South side to North in a few hours but you have to watch the weather as it can change quickly and as noted before there is very little shelter. Having said that the coast is stunning.
As for charter boat skipper shouting that's Inverness all tourism and nothing else
Used to run a charter boat furhter down the coast and we were just glad to see other people
Oh and the Firth further east isn't crowded.