You're best bet for parking would be the main Buchan Park car park off the A2220 (along the Crawley-Horsham road). This car park is closed at sunset. At the end of the car park you will find an information centre for the Country Park, well worth a visit if you find it open.You won't actually need to walk around the main pond to get to the cache but I'd recommend you do so, if only to see some of the strange and wonderful sculptures dotted around it!
I believe the park is technically in Horsham (though the car park is in Crawley!) but is much closer to Crawley homes than Horsham ones. The park itself is criminally underutilised by residents of the towns, especially compared to Crawley's Tilgate Forest, but I for one like it that way!
There has been a recent and aggressive policy of coppicing throughout the park so don't be alarmed if you see a lot of fences around - those are to keep the deer away from the new growth, not humans. There are regular gaps in the fences for visitors to pass. These are not fences around private property (though if you wander too far you may find some private property - these are clearly marked.)
I don't trust my GPS coordinates too much, so please let me know if you have better ones for this cache, thanks.
To start this cache off I've left:
2 x www.staggeringstories.net 2 CD Promo Sets
Myst Masterpiece Edition Game for the PC
The Simpsons Comics Royale Graphic Novel
The Complete Goodies book
Guide to Astronomy book
Staggering Shaggy Travel Bug
I've also left a disposable camera - please feel free to take a photo of yourself!