Richard/Jaime,Through a travel agent friend of mine we fixed up a 2 day trip. It involved a mini bas (collection from your hotel) and a drive up to Ayutihaya (spelling!!).
After doing the temples we joined a converted, junk like boat and cruised down the river in style.
If someone was doing Ayutthaya as a one-day trip from Bangkok, would you say that's enough time to have a decent enough look around the main temple sites, bearing in mind half the day will probably be spent travelling ?
Thanks,
Burger