An ideal way to do Dun Caan on Raasay is to simply go over as a day trip.If you take the car, you can cut a lot of the time /distance by driving to the high start point(signposted) for the walk instead of a village start.
The views are out of this world.
My own list of favourite hikes on Skye in this link, if of interest, including a link to a write up in detail of our Dun Caan hike winter 2023.
https://annestravelsandhikes.com/2017/05/25/my-favourite-skye-walks/
I’d second skyegirl’s suggestion of an Elgol base (or down that southern end of Skye, if anything is still available.) The hike from Kilmarie parking area to Camasunary is, for me, my top relatively easy hike on Skye.About a 200m climb each way if you go right down to the beach(which you should.) Absolutely glorious walk.
This route can also be continued by strong hikers up onto Sgurr na Stri, below 600m in height but probably the best mountain viewpoint on Skye with the Cuillin rearing all around.No technical difficulties at all but map and route details understood.That add on makes it a 7-8 hour day instead of half that.
You also have the option of doing the boat trip from Elgol to Loch Coruisk, involving a short walk to the loch itself once off the boat.Truly Gothic mountain and loch scenery amidst the Black Cuillin.
Glamaig is also superb but it’s helluva steep( not technically, just grass/moorland and it has a path) but the views are out of this world too.
Beinn Dearg Mhor at Sligachan also gives you a mountain hike with no difficulty apart from the slog!
You could also escape the crowds at the Quiraing and head along the Trotternish ridge in the opposite direction to everyone else , making for Beinn Edra, or as far as you want to go.Sensational views and perfectly easy walking on a clear path.
The Storr also offers an excellent hike to the summit itself.
Definitely hire a car.