I'm a fan of Paul Terhorst, who retired young, wrote a book about the experience, and now travels the world with his wife. His home page tells the story, and always offers a picture to go along with the words.
In his book, "Cashing in on the American Dream," Mr. Terhorst recommended living on a $50/day budget. The book was published by Bantam in 1988, so that $50 today would be worth about $80 (based on a 2.5% rate of inflation.) So, for a couple, could you live on $4800/month? I definitely think so! Where do you come up with that money as a military retiree? If you live like the Terhorsts do, you'll sell everything that has real value, including your house and car, convert your money to interest bearing accounts, and hit the road and never look back.
More conventional types will purchase a modest home in an inexpensive region of the country and set their budget based on the $4800. 25% will go to housing, or $1,200/month. Can you buy a house for that? That or less in many parts of the country, especially now! The rest will go to necessities like food, insurance, utilities, transportation and so on. Your health care is taken care of by Tricare for life, just remember to budget for your deductibles and co-payments. You'll still have money for plane fare for Europe!
Next time, I'll research some home purchase examples from among the areas that I'm considering for retirement, like Oceanside, CA.