6 Flags Discovery Kingdom - Flash Pass?

[egritz]

We (DH & I) are planning a trip to our local 6 Flags, Discovery Kingdom in Vallejo for my birthday. We will be going on Monday July 12th. Will it be busy? I'm wondering if it might be worth it to purchase the Flash Pass. We haven't been to this park in 6 years even though we live only an hour away, and I don't plan to go back anytime soon; hitting all the big rides is a priority for me.

TIA for any help