I'm not sure about the forms we have to fill out but I can give you some insight to our philanthropy.
Even though we are one of the smallest chapters on our campus, we have the largest Greek philanthropy! YAY! Haha, okay.
We have something called "Run for the Roses" with is a 5/10 Run/Walk to benefit Juvenile arthritis. While it is only a one day event, we plan for it YEAR-ROUND.
For the PR aspect, we always walk around with registration forms once registration is open and try to recruit people face-to-face. There is also an online registration system.
In the Greek community, we do dinner announcements at all the Greek houses. Within the college community itself, we make flyers/table tents etc.
Also, we work together with a local running club which offers some great support. I think having these run/walks are great because it appeals not only to the greek/college setting, but also to those athletic people within the city/town community!
If a chapter maybe does not want to host it themselves, maybe it could simply be a Greek community philanthropy to benefit the greek community as a whole...
Sorry if this didn't make a *bunch* of sense, feel free to PM me to clarify anything