Sure, you can give current members access to the event by simply assigning the track to your memberships. It's a great way to include the event in their membership price.

If you're looking to charge an entry fee, create a 1 class punchcard and only assign the event track to that membership. You can blast out the sign-up link/QR code to your current members or non-members looking to participate OR have it visible in the store to current members for easy purchase.

*I (personally) would not set an expiration date for the punchcard as the event may be weeks or months down the road.