It is an interesting concept. Get someone to grossly overpay for a ukulele in the vein of a donation.
I don't know too much about the FCRTP other than what is on their site. Basically the county would get 28 miles of railroad line and convert it to a trail. Sounds pretty cool, but not sure what the cost would be over the long haul. The truth is, it could be a good thing or not. I imagine that there are people lined up on both sides of the issue. But this is not a donation to a organization that is feeding starving children, digging wells to bring fresh water to people who have a high disease rate, or even sending supplies to those impacted by tornados or floods. This is for a hiking trail.
There is something a little odd about giving $10K for a $1K ukulele to help a trail, when someone could spend the $1K on a used Kamaka and give the rest to a charity of their choice.
John