Well you could be counter-intuitive and start by flying to Europe in January as cheaply as you feel comfortable doing, start your RTW there (CAI, WAW, IST, etc.) then go to Thailand eastbound, then back to the US, do your NA segments, then end the RTW back in Europe when you go in the summer. If you want to use FF miles to get to the jumping-off point, you might need less for a Europe hop (or wait for cheap winter fares or the ilk) than you would to go to Thailand directly.