I have landed on many AFB's for official business, but the final approval comes down to the base commander and airfield manager. There are a hold harmless, proof of insurance, and a PPR required. It helps to be in radar contact and on an IFR flight plan. I always call OPS as well as security forces with the arrival window, since they might not necessarily be talking with each other.
If there is an alert mission or live ordinance on the ramp, you can forget about it. If you cross the red line at other than a controlled entry point , likely the SF will be unhappy. Under certain circumstances deadly force is authorized, like (guessing here) if AF one is on the ramp, they have nukes, or high value assets like AWACS around. The security forces can and will have you on the ground eating concrete until they can be assured you are not a threat.
Then, after landing at a military base, how will you get off the base without local transportation and no GA services? More importantly, how will you get back onto the base without a military ID?
Dual use is obviously a different story- just don't taxi onto the military ramp without the paperwork in place first.
So, unless you have some real business being on base, it probably would not be worth the trouble.