I'm planning a RTW trip for the upcoming year(s) and have hit that point of deciding between an upright, a bent, and possibly a crank forward (just heard about those). My travels will take me through Japan, from Singapore to Chiang Mai and down to Cambodia or Laos, along the Indian coastline, and then from Istanbul to Spain. I start with a cross-America route that will have me fully acclimated to the bike before I go off to Asia.
I like a lot of features about the 'bent- cycling so far isn't any more valiant on an upright than on a bent, just more painful, imo. I'd feel more comfortable being able to see what's going on around me. It's a little harder to steal, from what I've heard. And it's not as far to fall...
I'm afraid of not getting replacement parts when I need them, though. As a solo woman, I'm also afraid of the bent making me even more visible or vulnerable than I might already be. Plus, who knows what the terrain will look like once I get out there (if you do, do tell!)
You might also check little details like ... are recumbents allowed on the roads? We had entertained the idea of travelling around the world with a tandem, but then decided to go with single uprights and it was a good thing we did. Turns out tandems are only allowed in certain places in Japan.
Another thing is this ... will you be using public transportation at all? Airplane, train, bus? We did, with our upright singles, and by the time we were about halfway through Europe, we had decided that the next time we do anything like this, we'll have folding bikes. Transporting the upright singles was a hassle.
Many airlines charge to transport bicycles, the trains in Japan don't take full-sized bicycles (only folding bikes), some of the underground in Europe only takes folding bikes, and specifically, the underground coming out of Heathrow, some trains won't take them unless they are boxed (Amtrak), many busses won't take them unless they are boxed.
And those were the hassles of ordinary single uprights. Recumbents have the potential of being even more of a hassle ... if yours is particularly long, you may have trouble even getting it onto the trains in Europe.
Recumbents aren't immune to being stolen ... a friend of ours had his locked next to the tent in a campground in Europe, and it was gone the next morning. It's often better to tour on something that doesn't look like much ... not too fancy.