It’s great to raise money for good causes, such as meeting the costs of the race or for donations and grants to hunger causes. The CHIditarod teams inaugurated the practice of soliciting cash donations all by themselves. This was really cool of them, and led directly to creation of the CHIditarod Foundation.
On the other hand, this was years into it. Prior to that, entry fees were expected to meet race expenses. You don’t need to get this elaborate. Start small. Run a good event. Keep the tone awesome (epic). Your event will grow at its own pace.
If you ask for money too soon — or for an event not yet well known — you risk being typed as just another charity, and there is suspicion in the land that not much money reaches those for whom it is intended. Earn trust. Keep good records and be able to explain yourselves. In the long run, you will be doing yourselves proud and you’ll know when is the right time to introduce this factor.