My partner and our two dogs camped at Fort Frederick over the weekend. It isn't the best place to camp if you have other options but we were looking to get out of the city with just a few days of notice. The campsites are very close together except for the youth campgrounds. Getting in and out of the campground is a pain since you have to go through a padlocked gate. The showers, water and bathrooms are very very far away (require a car) and outside of the gate. You're limited to portapoties as your only option near your campsite. You must bring in all your water too. It is also very loud at the campground due to the train which sounds like it is two feet from your tent. The cicadas at night are insanely loud too but at least they are natural. 

The highlights are the nearby river, cheap price, cute beaver pond trail and the fort itself. There are some nice hot showers, they are on the opposite side of the bathroom facility but you have to bring your swimsuit because they are open air.