When our club was homeless, we found a paintball field to use. Our deal is that we pitch in with help around the field (clean-up, building shit we'd use anyway) and generally not annoy the paintballers.
Of course, when buddy over there is showing off his Tippmann, and one of our guys pulls out a FMU C8A1, they tend to go OMG WUT'S THAT?
Your best bet is to be friendly, open, show that your club is self-sufficient (i.e. no PB staff has to come out to babysit) and that you're willing to pull some weight around there. Worked for us.
The only downfall is the blanket insurance policy that limits all paintball guns to 280fps. I know what you're thinking, the surface area energy transfer and kinetic energy of a 6mm BB is not anywhere near a paintball's, and you're right. But until the insurance policy is reviewed, it's not worth arguing and the 280fps limit applies to all the toys, airsoft or paintball.
So be prepared for that. If they have an airsoft clause recognizing the difference and ability to fire safely at higher fps, all the better...if not...well. 280fps all around isn't that bad...it allows for the abolishment of mercy rules.
Age Verifier - Lower Vancouver Island
Brotherhood of Nod - Nod Prime || Vancouver Island Airsoft League - President