RE: how hard would it be to start a flying club?
I'd put up a notice and see how many people you get interested. There will be some grunt work to make a smooth runway area initially, and of course, regular maintenance on it afterward if it's grass. The workload can get pretty high, so having a few guys to spread it around is nice. You might consider contacting other AMA clubs within 50 miles of yourself. They may have members close to you who have been driving because there wasn't another option. If the only requirement is donating some time every year, some may opt to become a member of both clubs, or maybe just yours?
Great advice above on making yourself the boss of it initially, but I would suggest drafting a simple set of rules and procedures just so the new membership knows what to expect. It would also be wise to include a provision for officers after the club reaches a certain size, because you certainly don't want to be the go-to guy for everything if you have 25 people using the facility.