Airport Access at a public airport is a pet peeve of mine.

I put up with it when we were considered ultralights knowing it was not really legal to refuse us. I used to give the airport the benefit of doubt understanding that a lot of guys flying ultralights didn't know airport rules and procedures. But now that I was sucked into the light sport arena and had to LEARN all the rules and prove that I knew them through tests and checkrides I no longer give the benefit of doubt. When I tell them I am a sport pilot and I fly a registered aircraft I expect to be treated as they would any other aircraft. I expect them to know the rules and not tell me stories of how a ultralight gave them problems in the past (I usually take this time to remind them again that I am not an ultralight).
Now having said all this, it is still far easier getting your way by being polite with a sense of humor. A smile and a handshake along with some knowledge of their airport and a list of your credentials will go a long way in getting permission. But, I have had to be firm on occasion when I ran into managers who want to stonewall you because of their inability to change.
EAA has a book you may want to buy that explains the in's and outs of public airports. It is a very valuable thing to have and I have even showed it to managers that were adament about not allowing me access.

Jerseyflyer

Bob,

You are correct, many don't say no they just keep you locked out. I have learned quite a few tricks as I travel around flying out of unfamilar airports, especially when doing the early morning flying.
First I usually call and ask permission in advance for the gate code stating I am traveling and fly an aircraft with a fold away wing and I would like to get it through the gate. I don't mention it is a PPC. This only works once in a while, but it is worth a try. If I have no luck, I don't get mouthey I just go to plan B.
The personnal gate code is usually something you can figure out like their unicom or runway numbers. If I can't figure it out then I pull out my mirror on a stick. This is an inspection mirror with a telscoping handle that I put through the fence and read the numbers from the inside. They almost always have them written down on the inside of fence. OR
There is almost always a button you can hit on the inside to open the personnal gate, again the inspection mirror will usually show you where it is and many times it is within reach. THEN
Once in that gate any heavy metal object passed over the inside loop will usually open up the large gate. I have found most times there is a shovel or pipe right inside leaning against a wall or under a bush for this very purpose. If not I just carry a tool box in with me and it usually activates the large gate when passed over the loop.

Now all this can be a pain and I don't usually do this. But if I have traveled far and have tried to do it the right way then I will resort to this method and have done so in the past. Surprisingly, I have never had a problem when I was discovered inside the gate. But when asked, I just play stupid and state that I am a pilot and I figured the fence is there to keep out the general public and non-registered folks. I must also add that I do not take the trailer inside the gate, just the machine. The trailer stays in the public parking area unless ok'd.

Jerseyflyer

When I first started flying I felt kinda nervous about asking to fly because I just knew they were going to say no. I now know they can't legally say no if its an untowered airport.  I'm a little more comfortable with it now and both of the airports I have called have been very nice.  The airport mgr did want me to stay as far away from the paved runway when I set up as possible.  I have yet to tell him that we are allowed to use the paved runway.  Seth

I have a page on my web site dedicated to access issues at public airports. This forum prohibits me to list my web address as a link. So go to airsportadventures (dot com) of course and click the "Access To Public Airport" page. I review public laws, FARs and FAA publications to help you overcome any objections by airport managers. Education is the key!