In reply to mike123:
I did the same as mountain.martin above but exactly in reverse a few years ago with a friend! Car at Mallaig, ferry to Armadale, back to mainland at kyle of lochalsh, up the west coast to Ullapool, ferry to Stornoway and back down to Lochboisdale!
Minimal planning went into it other than a cursory look at Google maps to check the distances were viable and it went very smoothly considering! Carried all our stuff which was a great experience and didn’t feel too much of a slog at all. Some absolutely stunning spots on both the West Coast and the Outer Hebs.
One of the plus points I think for carrying your own stuff is you can decide how long you want each day to be (within reason) based on how you're feeling/weather/etc....I really enjoyed it so would just say don't rule it out!
(and don't do what I did and fall in love with a couple beautiful big round stones on a beach and then carry them for the rest of the trip!)
Post edited at 16:02