The picture you are posting is from outside the base. And I found a few images from full-size trucks and even vans on base. So it can be done.Attached is a picture of the carpark at the gate of the naples naval base.
I have talked to a few people around the web since posting this and I actually feel more confident in taking the PW over there. One person I respect who drives a Defender 130 to many of the places I want to go has said he often parks outside a city if he wants to go into a metropolitan area in Europe and takes a taxi or uber into the city centers. He said this is actually better because he doesn't have to search and pay for parking. He said that once I get out of western Europe the size won't matter much.
I think I am going ahead with the plan to take a full size with me when we get stationed over there... I will update this site regularly with how good or bad that decision ends up being lol
I have thought about a Defender 110... but am just so unsure about the 4x4 system (center locker but no axle locks?), engine options and comfort compared to a new PW
the worst-case scenario is I only drive it a few times to eastern Europe, northern Africa and only a few other places the 3 years I'm over there... I still get to bring it back with me and enjoy it here. If I only get to drive it once every 6 months or so then it won't be such a big deal... but it will be fun in the desert of Morroco!