My husband, myself and our 18 year old daughter took a two week tour of Scotland and Ireland this last summer. It was our first time there. We are from the United States so things were very different for us. We drove a rental car but beware, everything is opposite of the United States. (Exit on the left, fast lane is the right lane, round-a-bout direction is clock-wise, etc...) We didn't make any reservations before leaving the US. Instead I devised a map of where we wanted to go with the map beginning and ending at the Edinburgh Airport. It's very hard to determine how long it will take you from one destination to another since the roads are very winding and there are different places to see and things to do in between. However, I did determine the general area that we would like to stay each night. I then researched and found different B&B's and made a list of them. I would reserve our B&B when we had a good idea each night of the area we were sure we wanted to stay. It gave us the freedom to take our time and do what we wanted without being on an agenda. We also only brought backpacks. I purchased our backpacks from IKEA. Each backpack had a day pack that zipped on the front, handles and wheels if we wanted to use them. The wheels also zipped in behind a panel when we weren't using the wheels. Loved them! They were also allowed on the airplane as a carry on. No fighting luggage crowds. Was also great when transferring between flights with different carriers.
Castles are amazing but they mean far more if you can learn the history of the area and the castle before going. Make a map like I did then learn about the areas within your mapped itinerary. One of my favorite castles was the Carnasserie Castle near Kilmartin in western Scotland. It's not gorgeous but it's amazing. You will be there the same time of year we were there. We had perfect weather, flowers in bloom, sheep grazing, sun shining....just sat on a little knoll and soaked in the gift of beauty from God. Perfect! Would have been the perfect place for a picnic. Our route started in Edinburgh then went to - Dundee - Perth - Laggan - Fort William - Glencoe - Oban - Kilmartin - Inveraray - Dumbarton - Ardrossan - (ferried to the Isle of Arran) - Glasgow - Edinburgh. We took many back roads through villages and seen many castles pop up out of no where. We stayed at B&B's and enjoyed local foods, stories and company from people from all over Scotland. I suggest being flexible with your schedule and enjoy meeting the locals. Another tip: Make a video/photo journal as you go and make sure to keep it updated daily. Otherwise, it's too easy to forget the amazing experiences you will have.