Please review our 10-day itinerary

I've been to Scotland twice without a car, so I understand your preference. However, I want to point out that the weather can be unpredictable and wet, especially in the western part of the country. With your own car, you'd be more flexible and could head in a drier direction. I originally booked a 1-day tour from Portree, but the weather forecast was poor (and that's the way it turned out), so I canceled at no cost. However, by that time there was no space available on the tour scheduled for the following day. I note that you have only one day in Skye and one in Inverness, so you wouldn't be able to reschedule a tour, anyway.

I acknowledge western Scotland tends to be somewhat less wet in May than in June (per statistics and per my own experience in 2025 vs. 2019), so it may work out fine. Still, Portree has almost 14 rainy days in May, on average.

I was in Portree in June (2019, so pre-pandemic) rather than May. In June it was very, very difficult to get a table for dinner without a reservation. I made it work by being at the door of a restaurant at opening time on two nights and getting Chinese carryout another night. Especially with a party of 4, you should make reservations. I don't know anything about the dinner situation in Inverness and Stirling. Edinburgh is large enough that you'll find something, but if you want to eat dinner at a specific restaurant, a reservation would be very smart.

I wonder whether you'd need to prebook the taxi from Armadale to Portree.

If it were me, I would add an extra day to Skye and condense the Inverness and Stirling portion from 4 nights to 3. Also, as acraven mentioned, without a car, it would be difficult to see all the beautiful places there. Even with a car, three nights in Portree (or thereabouts) would serve you much better. Also Inverness is going to be much easier with a car.

For example, on day 5, you can rent a car in Armadale (I don't think there is a car rental agency in Mallaig) and take the ferry with it over to Portree, then sleep in Portree. Day 6 and 7 would be spent exploring the Isle of Skye. Then on Day 8, you could leave Skye in the morning for Inverness (still with your car). That would give you time to see some of the areas around there like the Culloden Battlefield and Clava Cairns. On Day 9, return the car in Inverness and take the train to Stirling where you can spend the night. On day 10, explore Stirling but take the train into Edinburgh for one final night there. There's a lot more to see in Edinburgh than there is in Stirling.

In terms of how expensive and feasible a car rental would be, I would just go ahead and check with the companies. And honestly, if it were me, I would be driving from Edinburgh to Mallaig and then over to Skye. You'll still see the same scenery, and you'll have a much better selection of cars and agencies to choose from if you pick up in Edinburgh or even Glasgow. And you will have the opportunity to stop at places that are along the way.

That said, there is a car rental company based out of Armadale called Drive Skye. https://www.driveskye.com/

Personally, I recommend Arnold Clark as they are wonderful to deal with, have great customer service, and are competitively priced. I can trust them not to try and push me for extra services I don't need, and they will explain everything in the fine print to you before you leave. You can rent directly from one of their offices or via Celtic Legend. Both have their advantages and disadvantages.

https://www.arnoldclarkrental.com/
https://www.celticlegend.co.uk/car-rental/

ETA: I also agree with acraven about making reservations for dinner and lunch while you are there. I was there in May of 2023 and if you didn't make a reservation at least two or three days ahead of time, it didn't leave many food options available. Mostly just pizza takeout or something like that.

I just saw the note about how you wanted a full day in Stirling to visit with a friend who lives there. That makes sense. In that case, honestly, I would just skip Inverness (or just drive through). The area is nice, but it's nothing like the rest of the Highlands. If you skipped Inverness, you could slowly make your way back to Stirling by going through some of the areas with distilleries like Speyside and others. That's a bit out of your way, but if you're leaving Inverness out, it would give you more time to spend on the road.

Of course, there will be other distilleries, and possibly ones that are more convenient for you driving from Skye to Stirling. There are other Scotland travelers that will probably respond with some other options as well.

I can tell you that once you're off the islands, driving in Scotland is much easier. I explored the whole area along the northeast and east coast and the roads were very well kept and almost always two lanes. But even the single lanes were easy to maneuver, and there was very little traffic. And this was the same month you are going.