We will be finishing a walk in Scotland (next May) in Pitlochry and will have 4-5 days to make our way to London. I was first thinking of a night in Stirling, then down the east coast by train to Durham and York. But then I came across photos of Mull and it is calling to me. I think we could manage 2 nights there and then head straight to London (skipping Durham and York, which we could visit on another trip). Would we be able to see much if we took the ferry over on foot? Is there any public transport on the island? Would bicycles be a realistic option? (I realize there may be weather problems there but have really enjoyed cycling in Ireland in May.) We don't need to see it all; just need a nice beach for walking, other natural beauty, and some good seafood for dinners. I now see from a train map that would could go north from Pitlochry to Skye (via Inverness) in about the same time. Is there any reason to choose on over the other (Skye vs. Mull)? Or are they quite similar?
I have not been to Mull, but have been to Skye in May. I don't know what the picture looked like. If it was anything other than desolate and brown, it was probably later than May. I am also not sure what you are seeking. Certainly there is nothing similar between Stirling, Durham, and York on one hand and Skye and presumably Mull on the other. If you want castles and Tudor style architecture, look at the cities. If you want desolate countryside, go for the isles.
I have been to both. And, it's hard to pick. Skye has a lot of history tied to it and very dramatic scenery. The Cuillins, red and black are magnificent and you can do a nice day hike up from Sligachan for a great view of Loch Cruisk. And the Trotterish Peninsula has great formations and beautiful scenery. Dunvegan Castle is okay, there's lots of history there and with Flora MacDonald, of course. Mull's history is more from the Viking times. There are two castles with Duart being the older with much history! Tobermory is a bit like Portree on Skye in that both have charming painted houses. Tobermory has a distillery, but so does Skye with Talisker. From Tobermory there are lost of wildlife boat rides. And then there is the ability to visit Iona and Staffa on a day trip. You need to leave from Fionnphort. Both are big islands and to be honest you won't go wrong spending time on either. If you're headed south immediately after, I might lean toward Mull, simply to give myself more time on the island. Pam
Of the two, I prefer the Isle of Mull and would return there before going back to the Isle of Skye. We traveled about by rental car a few years ago so am unable to give advice as to biking or public transit. A quick Internet search can likely produce the information you desire.
The transit front is difficult for either island. They are such a big islands, that biking is probably not a good option. You can take public transit from Oban to the Ferry and then connect with the bust to Tobermory. I don't remember a beach, but I wasn't looking for one. But having just checked the web, I think I missed out. :( And, there is at least one taxi service.