Security is somewhat... minimal... but kinda keep things low key.
Depends on the landing pattern
You can get some good shots of Tradewinds, TWA, and Kumpuchea L10-11s down on the south of the field near Market Street.
If you go over to General Aviation you may be able to spot and take some snaps of the Foreign Carrier planes that are at Timco.
More than likely, they'll be landing from the North (sorry, it's been a while since I've flown in or out of there, so I forgot my runway headings). If you go up Bryan Blvd and take the FIRST exit north of the airport (should say something like "To Old Oak Ridge Rd") take that exit, go straight across Old Oak Ridge Rd and keep a low key there, you can get some good shots of planes coming in. You can see the end of the runway well, and one of the Taxi-ways ends there as well. And the Cargo Terminal sit there (where there is usually a 727, A310, 3 L10-11s, a DC9, and MD-11 there).
The east side of the airport is virtually worthless for spotting (i work on that side across the street from TIMCO).
It should be realtively safe to spot. I wouldn't draw attention to myself though. Play it safe. And don't push your luck by walking along the fences too hard.
And, try to get a good shot of the new Tradewinds L10-11 and an Air Canada CRJ.... i;ve been trying to get good shots of them for a while now.
Best of luck.