These are tough questions. It may be possible to hire third party marketing companies that would be able to do some testing for you to give you the metrics, but most likely the best option would be to do the testing in house. I think that you would need to set up a few of these alternative sampling methods and go out and do some A/B testing and see which have the highest ROI. It would be important to pick some metrics that you could use to measure that which would be uniform for each location so that there is no variance between what is being measured. For example if foot traffic to your booth is a goal then figuring out the best way to measure that or if actual sales is a goal that is much more easy because you can just weigh the cost of the event against the revenue generated at each location. Feel free to contact me for more in depth conversation about this. You can find me at email@example.com or at my website www.gscsconsulting.com
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.
Most likely the best way to get funded in this situation is to approach independent investors. It would really depend on your business plan and whether or not you have an attractive business model. You could try to get connected with networks or consultants that have access to independent investors such as chambers of commerce, or consulting firms Global Strategy Consulting Services, LLC www.gscsconsulting.com or you could email firstname.lastname@example.org and someone will respond with ideas on how to get you funded.