At the time of my visit in 2009, the structure was closed for renovations. It has now re-opened to the public and is worthy of a visit since you could explore the park at the same time which is located nearby.
The architecture is a blend of neoclassicism and "cineserie", which was in fashion at the time that the structure was built. The curious mixture of styles give the structure, in my opinion, an air of fantasy, as if stepping into a story book with its bright colors, Chinese prints and silks, and the "oriental" bells that adorn the railings. Check out the video below with offers a wonderful video "tour" of the structure.
(this section is under construction while I do some research on transportation options...!)
If you have a car, it's probably best to drive. Failing that, you could take a taxi. From the Giardino inglese, it is a 3.5 km walk north, probably more difficult during the hot summer months.