Im lucky enough to live about 20 minutes away and have visited severall times now. The place is full of history and you get a real feel of how it would of been. I also went on a school trip and was lucky enought to sit in Micheal Schumachers ferrari! My teacher new how much i love motor racing so when the tour guide said anyone wanna sit in it, she said "i think i know someone who does "
If your going to visit i suggest a sunday could be a good day, every now n then they have old classic car days. I drive past on the way home from fishing (que the old man jokes) and see loads of lovely old cars pulling out.
As for the hill climb test, i have watched caterhams (spelling :/ ) doing that, one of which burnt the clutch out
Certainly worth a visit