I am going to be in Paris for 3 days. I am thinking of a day trip to the Loire Valley to see the Chateaus. There are several choices (touring bus, minibus)and different prices for the trip, one includes a trip to Ambois. Any suggestions?
If this is your first visit to Paris, you should make a list of the tourist sites you are interested in, and figure the time required to see them. You might find that the entire 3 days are needed just for Paris sight-seeing. If after this you are still interested in day-tripping to the Loire, your choices are: train (still have to get to/from the chateau once there), tour bus (least headaches as far as transportation), or rental car (easy or tough, depending on where in Paris you pickup/drop off the car).
If you choose to do this by car, research very carefully which chateaux you want to visit, and make sure they don't sit at opposite ends of the region. At a gentle pace, you can probably visit two, or maybe three if two sit particularly close to each other. Don't shoot for any more than three, though.