In reply to Mostin3:
My wife and I "back-packed" in East and South-East Asia in 2012. We were then 61 and 56 so not the normal age for back-packing. It was part of a post-retirement "grey gap year".
We started in China on the wrong foot really, booking into cheapish hotels with local clientele. We only found our feet when we switched on to the back-packer friendly hostels. We thought we might be out of place in these, but in fact most had en-suite double rooms as well as communal dorms (pricier of course but still very cheap) and a clientele of all ages. The key thing with the hostels is that the staff, mostly student types, speak English, understand backpackers and will steer you around the pitfalls that can trip up the unwary. Also of course, your fellow hostellers are a fount of good advice. Once on this circuit we found it quite easy to get sound recommendations where to stay at the next place we were going to.
We slipped off the hostel trail a bit in Vietnam and Cambodia but I think similar places exist. Back onto it again in Thailand.
I'm not sure if China is on your itinerary - it's well worth it. I didn't climb in Thailand - wrong season really - but I did climb at Yangshuo in southern China. Stay at or visit the climbers' hostel in town and you'll certainly find people to climb with. I just took a harness and rock shoes and tagged along with others - Europeans and Australians - who had ropes and quick-draws. Climbing in June in a humid 35 degrees was interesting, but there were quite a few climbers about.
I did two other interesting trips for mountaineering types - nothing more than walking on either of these but quite spectacular. The "Tiger Leaping Gorge" from Lijiang in south-west China (Lijiang is well worth visiting anyway) and Kawa Ijen, a volcano in eastern Java, which is accessible as a day trip from Bali - with a 3.00am start. Just ask at hostels or tourist offices.
There were two of us of course, but I did all of the climbs and walks solo as my wife doesn't go for these. We met quite a lot of folk who had started solo but most had pretty soon joined up into pairs or small groups. All very friendly.
Have a great trip.
Martin
Have a good trip.