Going on day tours by bus is a much better idea, with such a short period to play with. I suspect you have no idea how slow & stressful driving yourself around Scotland would be - an average of 35mph is good going, without stops. But if you are mainly interested in seeing the country, why not take one 3/4-day tour rather than several day tours ? You'll be going over a lot of the same ground each trip. Rabbie's does always seem to get the most plaudits, and their buses are smaller than some (which I think is a good thing).

Wondering about your 1 day in Edinburgh too. Would I be right in guessing that this is the day you arrive - after an overnight flight ? So you are devoting less than a day to Edinburgh ? And the Sheraton isn't that near Edinburgh Castle, it's about a 15-20 minute walk uphill. Although you can get the hop-on hop-off bus tour nearby.

Thanks for the advice keith_l and caroline_edinburgh

We will do the day tours this trip and feel it will give a good education with experienced and knowledgeable guides for a first time visit.