The ACC-Whistler provided the following update regarding the current understanding for backcountry access through Whistler Olympic Park.
If you are entering WOP during open hours the access fee is per vehicle not per person. If one of the people in the vehicle has a WOP/Ski Callaghan season’s pass there isn’t an entry fee.
The Alexander Falls parking is “really for” ski tourers returning through WOP after hours or for people going overnight. It was not designed for early access prior to WOP opening. However, unofficially people do use it for backcountry access before WOP opens. There isn’t a fee in that case.
During much of the ski season WOP is open until 9 PM on Wednesdays and some Friday nights. This is clearly the best time to go if those days work for you.
If you park in WOP you need the dashboard info sheet displayed in case of emergency. Even at Alexander Falls this would be useful if your vehicle is there after dark.