One thing you might think about is talking to your local town's mayor, tourist information group, parks department, YMCA, or coffee shop owner. Try to be an organizer and be ready to tell them why your idea would be in the communities best interests....and it really is too !!
You could start your rides at the coffee shop or end it there. You can pitch your idea to the community as being a route that rides through the towns commercial district or along quiet century house streets, you can pitch it to the YMCA as an adjunct to their goal of exercise.
Make a flyer that you can put up around town, maybe even on your local cable community access channel. The be prepared to stop riding like you usually do so that you can do a community/club thing. Develop two rides per week weather permitting and by all means look into the MeetUpGroup thing online......it is wonderful for this kind of grassroots stuff. Be ready to do something like we do here: a Thursday evening "noone left behind" ride for the general population. This is a ride that accomodates any rider of any skill or age and it is usually around or less than five miles. As the organizer, stay with the slow group and encourage them and take pictures of them riding and then post them to your new MeetUpGroup page (the MeetUpGroup thing is free by the way). Everyone likes to see themselves on a page on the internet right? This is easy stuff to get people to commit to.
For the more hardcore riders that you might have and know you might bring them in as collaborators on this project. They will have to be given a ride also so make it a Saturday morning ride with routes and roads around your town that they know. Again, this is where MeetUpGroups comes in handy as you can map out routes and allow others to map out ones too. As the administrator of the MeetUpGroup you will solicit input from the community and change your plan to fit what the people want to do on their bicycles. Most of us are followers and like to ride with other people, leaving the organization to others....you will also find some who want to be organizers so let them do the work. Don't get hung up on being the leader of anything.
By the way, if you do have a core group of friends that like to ride then have a party at the park for them with BBQ and beer and bikes and in the middle of it present your idea for a club. Then when you get a volunteer, maybe a best friend, hold them to the organizational aspects of the whole thing. Above all don't be discouraged by slow numbers joining.....I promise you that you really don't want to be the boss of any of this stuff but if you don't initiate it, it won't ever happen.
In my little town we started one just like you are describing. What happened was that a local guy got laid off and started a bike shop. He sells bikes and started the group for a way for his customers to ride together. The old hands really do stay back on Thursday for the newbies and on Saturday mornings, due to the information being available there is now a short ride and a long ride for those hard core bike folk....but they all start off together.
Hmmmmm.....here is the link to our group out of MeetUP. There are links there back to the bike shop. These are all very different people but they all share a mutual attraction to bike riding:
http://www.meetup.com/REVOLUTION-CYCLES
Best respects,
Pat