Yep, my daughter and I both have Crohns and both ride. Ride, hike, swim, ski, work more than we oughta. I'm not in all that great shape, but I'm still pretty active. And DD is training for the California Aids Ride 2007! Two words of encouragement for a new Crohn-ie:
1) Not that I'm a Mormon (far from it!) but according to one historic Mormon elder "The secret of a long life, is to get yourself an incurable disease ... and take care of it." Now THAT I do believe.
2) I just read in a local science magazine that somebody at my university has come up with a new mechanism for stopping auto-immune diseases (Crohns falls into that category). So far they've done the mouse tests on this for one skin disease, because then they could apply it as a cream. The mouse tests were successful, but there are still some years of human testing to do before it can go on the market. And for Crohns they have to find a different way of delivering the medication to the affected areas. So we'll still have to be patient, but at least there are new approaches under development.

Which I guess brings us back to your goal: Yes, there seems to be good reasons to do fund-raising for Crohns. There is research out there to support, and support group work to support while we wait for the research results. I wasn't aware that there were Crohns rides anywhere. Glad you found some. Perhaps others could be organized (talk to local bike clubs? bike shops?). I also wasn't aware that one could self-declare fund-raising goals for other, non-charity rides. Hmmm. Maybe we Crohn'ies on TE could find a weekend when there are rides here and there and overlay those with a virtual charity ride for Crohns ...?

As for raising the funds, there are several threads on that hereabouts. My DD has started her fund-raising for ALC. She's got letters printed up to send to friends and relations. She's made cards to insert into bags of cookies she plans to sell at her own and her BF's universities (took some calculating to work out what to charge for the cookies, but I guess she's got that done too). And I gather her BF wrote a piece for the local paper. Sister Trek420 also gets some sponsorship from the firm she works for. They contribute money and I vaguely recall that Trek proposed they make team jerseys the company's riders could all wear one day of the ride. That could be quite a PR show for the company if they all rode out as a group, for instance. I'm sure you'll find other tips in threads in this theme area.