Short and sweet answer Roger! Hayley, I suggest you look at the Reviews section where there are a number of threads regarding the Thailand tour. I've be on JY hols with a number of people who have done this tour and they all loved it. I gather when you are in the north of the country, there is a brief forray into Laos as well! Seemingly it is a very well balanced tour and the few days at the beach resort at the end also seem to go down very well with the people I know who have done it.
Hope this helps!
Bob