We have found a good source for booking quality small guesthouses and Bed and Breakfasts on the web, namely:
You can also access information via Google Maps by typing in "B&B" or "Bed and Breakfast" when you have a map of the area open on your screen.
Generally you need to book a villa or an apartment for 3 or more days, probably a week in high season, but for a family with young children this can be an economical way of enjoying the area.
The terms "holiday apartment", "villa" and "letting" are used to cover the various options.
A good provider of campsite information is Eurocamping.