In my opinion, the Religious Naturalist Association should levy annual dues.
I think it is reasonable for people to participate without paying, but having dues shows a commitment.
This is similar to what we do at our Unitarian Universalist church. We have pledging members, but anyone is free to come to a service and otherwise participate.
I propose two levels of membership: Basic at around $25 USD and full membership at $100 USD.
As far as projects go, I suggest that the projects are directed to the furtherance on religion as a practice. I do not think that we should do anything on ecology or policitcs or social justice or economics. There are other organizations for that. I would prefer that we spend our time and effort on furthering religion.