For Clare, Limerick and the west coast, start with the passengers, luggage and child seats you need to carry. Compare boot capacity and transmission before moving up to a larger vehicle category.
A small car can be easier to manoeuvre at village accommodation and public car parks. A larger vehicle can suit extra luggage, but check its dimensions against any parking height limit or narrow final approach.
Reserve an automatic explicitly if required. For an electric car, check charging at overnight stops, the payment arrangements for public chargers and the required battery level when you return it.