I think it's a great idea.
MAX BMW Motorcycles is working up something similar for the Northeast. Some events will be scored and others will be fun runs. Some prizes will be awarded based on points scored, others will be raffled so all the participants get a chance.
It will all lead up to the Color in the Catskills where the big prizes will be awarded at the Saturday night dinner. The grand prize will be raffled at dinner with participants getting a ticket for each event they completed to encourage participation. It will be a game of chance and the winner must be present.
What I see as your biggest challenge is finding 400 riders who are willing to throw $100 to compete for a new bike, especially if they also have to pay fees to attend each event too. The way I see it is I know that there are plenty of better riders so my chances of actually winning the grand prize are slim so why spend the $100 to enter, especially if this is an add on to established events that have their own fees.
Ultimately I think your biggest challenge will be developing a scoring system that is easy to understand and above all else fair. When scoring things like social media posts and such it becomes much harder to be consistent and fair. When 22 grand is in play the rules and scoring need to be bullet proof.
It's a great idea and I hope it can come to fruition. I'm very interested in what can be done to encourage the guys like me who love to compete but know we'll never win to come out and play.