We will be traveling in Edinburgh in May 2017. I looked at the two websites for small group day trips to the Highlands that Rick recommends. Rabbie's site appears not to be accepting reservations beyond March 2017. The Heart of Scotland (wee red bus) site shows no openings for May 2017. Surely they aren't totally booked that far ahead?? Perhaps they aren't taking reservations for May yet but their site shows "unavailable" instead of "not yet taking reservations??" Or could they really be booked up?? Has anyone booked with either of these companies ?
I really think that you are too early. Try next month, and if that doesn't work try September. Or, just contact them and ask. Heart of Scotland. Rabbies Tours.