Jeez. $65/day? Be travelin' in style for sure.
Let me suggest another approach. Have the charity act as your official sponsor. Let them set you up a website for donations to THEIR cause. Make some business cards, wear a shirt advertising your charity, placard the bicycle. Do what THEY suggest you do to raise THEM money, including financial acountability.
Then accept donations from people for either the charity and/or your personal expenses, depending on the donors preference.
I know a man who walked from Bellingham, Washington to Key West raising money for cancer research who followed the above formula. Worked out great for both he and the charity. Rarely stayed in a motel. I know another man who walked across the US, self funded, who raised over $100,000 for his international charity.
Another approach is for all donations to be made to the charity who then in turns sends you travel expense money.
Good luck.