I see. Not many V-Stroms here. Not sure why.

A Suzuki DRZ400 will be quite light and good for long distances, although won't have the same ability to carry a passenger/lack of panniers etc.

Quite a few Versys around and I think that would be the best choice (unless you really want 21" front wheel). Same for Transalp 400-650 and Africa Twins (though those aren't very light). Many available. You might also consider one of the smaller BMWs (650-800cc).

As mentioned the CRF Rally is a good option, although a little under powered at times. Keep in mind you're not riding as fast here as in Thailand, so there's never a big need for significant power.

Do you have Honda CB500X