Yeah Sumas Mtn. is awesome, it's practically my back yard... I haven't been through it since I had my turbo CRX but once I put some coilovers and an exhaust/intake on my DC2, I'll be sure to test them out there. I love it because there is a bit of everything- lots of technical corners, long ass sweepers and long enough straights to really get ripping! Heres a better GoogleMap for those who want to check it out.
PS Straiton Rd makes for a wicked Longboard run also :P.