I don't believe that Challenge Park is open after CP closes for the night, except for overflow reservations on Ripcord (which you would have to get before it closes anyway). As for the driving, the toll booths will direct you where to go, no problem.
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PO!NT OF VIEW - A Different Look at Roller Coasters
http://www.crosswinds.net/~justmayntz/thrills/ Closer and closer to 100 VOTES and a new POLL!