Posted 24 September 2010 - 07:35 AM
Like Caverat, we've found that in-person meetings are the way to go.
Another option is to approach the situation as a photographer would. Most National Parks will let you take still images during the day without issue, but as soon as you move out of areas open to the public or want access before or after the park's posted hours, you'll probably need a permit.
The rules are different for every park, but our state parks operate under the same basic guidelines, as do our county and city parks. Permits can be as little as $50 or as much as $600, depending on the location, and they might require you to pay for staff to be on hand. Another common requirement in our area is liability insurance, usually naming the City/County/State as an additional insured.
Finally, there are many venues that you can just flat-out rent. For a set fee, the property is yours for x number of hours- not the most inexpensive route, but effective for gaining access.
As Caverat said, there is nothing more important than projecting a professional appearance and making the proper contacts.