You are very to be in a place where it is so easy to travel from be it by bus, train, plane or even a ferry!
While you are here, you should take advantage of the close proximity to Europe. There are many ways to get around Britain and Europe.
You will need a passport to leave mainland Britain. You can get one after you arrive but it is less hassle if you get it while you are still in the States. If you are looking to travel on your no fee passport, you need to see if the country you are going to accepts them. France is one that doesn't and with all that is going on in the world, I would distance myself from the military as much as possible while on vacation. You can check the entry requirements of the country you are going to visit here.
One of the best websites I can suggest to find your way around and to see what your options are to your destination is Google Maps. I use this to find my way whether I am walking, driving or taking the train. It even factors in walking times. I also like it because it shows a few options on how to get to your destination.
Looking where to park? Go to Parkup.com, its easy to use and has great info.
You can also book a vacation through off-base travel agents. This can make it easy, affordable and do not charge a fee unlike ITT. You can book online or visit their shops. A couple of local travel agents are: First Choice or Thomas Cook.
Being stationed here may cause you to have an increase of visitors from home. Just remember, they can stay for 6 months without having to get a visa. An easy way to get them here without having to drive all the way to Heathrow is have them take the National Express. I do this with my visitors. The tube/train combination is not great especially if they have not packed lightly. There are stairs and its packed not a pleasant way to travel after coming all that way. They can upload their luggage once and they don't have to get off until they reach their destination. This was a Godsend with my Aunt's six suitcaes