West Coast Experience
Sounds like you've got it worked out well ahead. I've flown quite a bit in that area with a similar number of hours to yourself, but have never risked anything other than concrete runways (OK, I'm a whoose!). That said, Plockton was very comfortable in a max-weight Tomahawk.
One thing nobody has said yet... need to think of your landing alternate in the event of bad weather. The weather in some of the valleys can be very localised, esp the Great Glen, which sometimes makes them impassable without an IMC. As has been pointed out, fuelling points are few and far between, and you always need to have enough to turn back for an alternate... which usually results in carrying far more fuel than is really necessary.
Those steep-turns you have to do for the GFT? You quite often need them for a turn in the valley without touching the cloud base, the water or the sides!
Should be fun though, especially in good weather. All the best, and enjoy. Nothing beats VFR "on top" in Scotland.