Is it Skye accommodation you’re having trouble booking, or a tour? And does Rabbie’s do their tour as a daytrip, returning to Inverness before the end of that day?
We stayed on Skye for several days and nights, and I really valued being on the island that long. We had a rental car, so getting around was on our own schedule (well, influenced by the times that sheep were lying on, or crossing the road), and it allowed us time to go various places on the island. Are you relying on someone else doing the driving?
While I haven’t taken a tour with Rabbies, I know they get rave reviews from people on this forum. If you’re just visiting for the day, they’d be worth looking at, but I’d recommend more than part of a day for Skye, if you have the time.