What languages do you speak?
There are several expat havens that have significant numbers of former US servicemen/women living in them..
Thailand, Panama, and the Philippines immediately come to mind..
Depending on not just the country, but also the region within the country you are looking at, language skills vary in importance.. Force example, if English is your only language, you'd likely have no problem in Phuket, Thailand.. but good luck being able to communicate with many people or get much accomplished if you live just 50 miles north east in Surat Thani...
Closer to home, I know of pretty significant expat populations in Costa Rica, Panama, and Belize.. At one point I was giving pretty serious consideration to Belize.. I found that property is inexpensive in the southern coastal area (was pretty easy to get about a 2,000 sq foot, basic house and 5-10 acres of land somewhere in the $60K range.. and "luxury" living in the north near the resort areas was pretty easily accomplished for less than $500K).. Belize is reasonably firearms friendly (not great.. but you can own them..).. pretty expat friendly.. etc... and english is the primary language spoken.. so very little challenge when it comes to trying to buy a replacement part for the car, or talk to someone at the local coffee shop, etc.. from a conversational point of view... Overall cost of living is substantially lower than even the lowest COL places in the US.. so stretching retirement dollars a long way isnt terribly hard.. you can live a reasonably comfortable life in Belize on a not so huge income..
All of that said.. Belize is actually a good bit more expensive than other Central America options.. Medical facilities for an older/retired person are a bit behind many other Central America options.. Policing there is... well... a complete farce.. and as a result crime in certain areas can be a serious problem.. etc..
All things you are going to want to take into consideration (in addition to who is trophy friendly) before making a final decision..
If you are a Spanish speaker.. Ive got a buddy that lives in an expat community just outside Mangua, Nicaragua.. he's probably the happiest guy I know living abroad.. he is huge into fine cigars and fine rums... and his life is full of them.. he's got a great house, on a really nice piece of property that is walking distance from the beach and is living a pretty fancy life on his meager US Army retirement pay.. but he'll be the first to tell you that if you dont speak Spanish and/or get easily frustrated by the silliness of most Central American governments.. dont bother moving.. you have to accept the bad to be able to enjoy the good.. and take life lessons from your dog (i.e. kick some grass over that shit, and move on....)....