Yes, it may be possible, but it depends on the base and their mission. Generally, since 9/11 it has become much more stringent,
Not true
particularly if the flight crew aren't in the military. You can call base ops and ask for the airfield manager, or your point of contact can talk with them. You will need to sign a hold harmless agreement as well as fax documentation regarding your insurance. If approved they will issue a PPR, with a very narrow window for arrival. It helps to come in IFR. Most fields will have a follow me vehicle. Do not taxi anywhere except where they tell you, and do not walk cross any painted red lines on the ramp- there are controlled entry points to get into and out of the red area, even though it's just a line. Since some bases have an alert mission, or have fighters with live ammo ready to go, the security forces take their job very seriously. Any deviation may find you eating concrete with a loaded weapon pointed at your head.
Unless you are intimately familiar with the procedures, it may not be worth the trouble.