+1 on finding people on tour soliciting donations for a "charity" as sketchy. I met Jon and Ashley, who are riding across the US and are doing it partly for themselves and for a charity. When I first started talking to them, they never mentioned that they were riding for a charity. They eventually told me about them keeping a blog and handed me a business card with their
website information on it. I had to ask them about the charity they were riding in part for. They said that they were riding for themselves and if they could raise some money for
http://pushamerica.org/ then that would be good.
It seems to me want to do this tour for yourself then do it for yourself. If you want to ride for a charity, have people donate directly to the charity. This way you will not come on as sketchy and people like myself, will donate to the charity because I know its going to them.