Luggage and bags:
Depends how you are travelling around. We had a car so we could either take bags or a suitcase. As we were only there for a week we each had a large bag.
Clothing/Shoes/Weather Gear: In the winter anything warm is best. It was chilly when we were there in October. It rained on and off so take an umbrella.
Toiletries and Medical Supplies: Most villages have a general shop where you can buy toiletries. Most towns will have a couple of chemists to get medical supplies.
Miscellaneous: Take a kite with you! There are many windy spots in Ayr, and if you have a stop somewhere during a long drive, get the kite out for 15 minutes. breaks up your trip and it IS fun!