I used to work on Ft Knox and there are a couple of options and yes, it's difficult if you're not familiar with the area.
You can't live due East of Ft Knox. Knox is a 100,000+ acre installation and most of the Ft Knox land is East.
West there are rural areas that are real close to Ft Knox. Bad part is that there are still not a lot of stores nearby and for some, that is a deal breaker. I lived about 12 miles West of Ft Knox (off of Hwy 60) and it was 9 miles to the nearest grocery store, 4 miles to the nearest gas station, etc. Enjoyed it and you adjust to not being able to quickly run out to the store. Exception may be Brandenburg (small town). Most places west of Ft Knox will take close you close to 45 minutes to get into Louisville.
South - Elizabethtown. Great city that is growing quicker than you're average small city in America. All the ammenties that you normally want in a smaller city except that you are traveling farther away from Louisville when you depart Ft Knox. Some like being farther away from Louisville (consider it an hour away from Louisville). The city was recently a 'dry' city which greatly affected national name restaurants from moving in but that has largely been resolved as more and more national chains move in as well as some bigger name hotels.
North is Louisville. Longer drive for hubby each day to work (minimum 30 minutes if you live on the SW side of Louisville). However, it's a 300,000 person city with more ammenities that you'd expect in a large city. Louisville is the largest city in Kentucky and combined with southern Indiana, it's a good size city that will provide most people with enough events and activities. Best thing about Louisville compared to the twin cities is that larger cities are just a short drive away (Indy and Cinnci, even Nashville).