I would use social media by running a Facebook ad that compares your scavenger hunt to PGO. You could say something like, Like PGO? come check out our new scavenger hunt! and then those who you get that come to your website you could use the FB Pixel to retarget them and create a look alike audience, then add in the look alike audience all of your key words that would suggest people who like PGO. Then Voilla you are right in your target market. If you need help, contact me and I can get it set up pretty easily if you have a website and access to the coding for it.