I’m in a tiny town more than 10 miles off the interstate with only 3 roads in and out. We’re surrounded by swampland, streams and open water so if we needed to keep people out it wouldn’t be hard to discourage them.
I would recommend your town purchase 6 (or more) K-rails (aka Jersey rails). They make excellent traffic control points. Add some sandbags and a couple of armed citizens and you can positively lock the place down.
What’s an interstate? We just have FM roads, ‘round here ;-)
More than 10 miles from the nearest interstate is good-keeps the transients away...