We visited the estate and gardens on May 2nd, 2007.
We just about crossed Stourhead off our list, but decided to make it happen and we are so glad we did. We had taken the five day Celebrity Constellation cruise from Southampton and returned there on April 30th. I had originally wanted to proceed to Stourhead directly from Southampton, then onto Bath, but having large luggage and the new security concerns made that plan difficult. We stayed at the Royal Hotel in Bath that night and the next day day and they locked our luggage up in a closet the next day while we caught the train from Bath to Frome. In Frome we used a local cab to Stourhead for Fifty Pound roundtrip. (the exchange rate was horrible for our entire vacation, but the sights and memories are worth it now) It was about a twenty minute ride each way and also a nice view of countryside and some great coversation with Ms. Angie, the daughter of the cab owner and a good driver. I had researched using the local Wigglebus service ,but was of the understanding that advance reservations were needed for the use of this rural cooperative service.
We used our National Trust cards we had purchased previous to the trip. (We considered these a great deal, also good at Roman Baths and Arundel and Exeter Gardens earlier)
The gardens were indeed lovely. Do not rush, Stroll slowly or as you prefer and take time to linger. Ask the volunteer's questions and they will tell you some great history and personal views on the gardens, England and anything else .
We are not serious gardners as some are, but Stourhead house and Manor are an excellent place to experience beautiful gardens and a slice of old and new English countryside life.

We were not planning on visiting Stourhead on our 30 day drive around England & Scotland. WHAT A MISTAKE!
Fortunately we had an afternoon free before leaving Bath & had a look in our British Heritage Pass book for something close by. (Can't tell you the entrance fee as was free on our Heritage Pass- well worth the purchase price, or can also join the National Trust at a lot of attractions, which also seems good value)
We went in May, 2006 and the rhoddadendrums were in full bloom- lovely in themselves.
The planner had an idea to make it so every time you turned a corner there would be a new surprise, & he achieved his plan. What wonderful gardens!
You walk around a lake, with views of a temple, bridges, lovely flowers & foilage, a grotto etc.
I had thought to visit only a few gardens in England, as they have never been one of my husband's interests, but after Stourhead he kept pointing out signs & saying was that one included in the Heritage Pass and we ended up seeing Sissinghurst, Wakehurst, Trebaug and Hyde Hall in England, as well as Drummond, Inverewe and Crarae Gardens in Scotland (to name a few)
Of them all, Stourhead stands out- they certainly know how to plan gardens in the UK!