Good thread. I suggest not only reading Billy and Akaisha's web site but also buying their e-book and studying it carefully. Also check out the invaluable book "The Practical Nomad" by Edward Hasbrouck.
We ER'D with less than half of your assets and have suffered in the market despite a very conservative, diversified allocation a la Bob Clyatt's RIP portfolio (and come to think of it, the investing section of his book, "Work Less, Live More" would be of great help to you). If you are looking for a truly defensive portfolio I would recommend checking out the work of Harry Browne and his Permanent Portfolio. There is a gigantic and very informative thread about it over on Bogleheads, and you can get the short version at this excellent web site run by one of its most articulate proponents:
About the Blog | Crawling Road
At the very least, read Browne's "16 Investing Pointers" on that site and you'll realize why having all your eggs in the muni bond basket is not a way to sleep well at night long term.
We've traveled extensively in Asia and Europe and currently live full-time in Mexico. The first thing I would say is if you want to get to know a place as well as be able to get a handle on true costs of living you need to stay for six months in a given place. That allows you to rent by the month at local rates rather than pay through the nose for tourist housing, learn a bit about the culture, how to shop and so on. Places advertised on the internet are never representative of local housing costs but are severely skewed towards the high end. This is totally true in the developing world and largely true even in Europe.
You can always follow in Billy and Akaisha's footsteps and rent for 4-6 months and then use that rental as home base for exploratory trips to nearby countries. If you really do want to speed through the world, relatively speaking, with only a month in each place you'll do better by reading up all you can beforehand and still choosing your countries carefully. The Hasbrouck book will be worth its weight in gold in that regard.
I envy you your choices and commend you for your diligent saving, hard work and spirit of adventure!