I think the key would be to get permission from whatever company is currently occupying that portion of the industrial park. The Navy no longer has ownership of the former Ellyson Field, as you probably already know, and I think that you could probably get legal authorization to hunt from whatever company is currently leasing the area that you intend to hunt. However, the large 'green belt' area between Ellyson and Scenic Hwy might be fair game without any authorization. I would certainly check with the county first to be sure.
I actually work out at Saufley Field and I've been trying to get official permission to MD on my lunch hour but no one seems to know who would be the proper channel for authorization. As far as base security is concerned, they have nothing on the books to prevent authorized personnel from MD'ing. But it would be my luck that some big wig from Pensacola NAS would be over for a visit and see me out there 'sweeping' and have a totally crap fit.
Let me know if you do get permission to hunt at Ellyson, especially if you want a partner to head out with. I live just a couple of miles south of there off Scenic Hwy.
Pcolaboy