You don't need to go inland to climb Munroes, Skye being a prime example where they rise almost out of the sea. There is a path round from Elgol into Loch Coruisk at the base of the Cuilins where you could easily camp and climb for a couple of days/nights and then carry on round to Glen Brittle.
I'd suggest starting in Oban and getting a ferry over to Mull, spend as long as you want in Mull, (Ben More is a Munroe) Then head north from Mull on the ferry to Lochaline and head on the road north west round the coast of Morven and continue on round to Loch Sunart then Ardnamurchan etc and go as far as you have time to travel.
Enjoy!