I Understand what you are saying.having just done 3 weekes round the world, 9 days at home and now just arrived in Asia again. not popular at home!
I spend about 8 months of the year away from home. iof that 8 probably 5 is in Asia the rest elswhere. What I started to do early on was make connections in cities/countries that I knew I would be going to or at least a good posibility I would in the future. I generally used Expat forums and forums that I had interests in, like this one. Lurk around them a while to see if there is a reasonable probability they are not axe murderers etc. the expat communities are a very good source for finding things to do other than just sitting in bars. I have done so much in HK, China and the US based on thier recommendations.
I have made some very good friends around the world this way that actually have similar interests and generally dont bore you to death. I hate having to spend all my time on a trip with customers, it means I cant relax. This way it means i dont have to spend night after night alone staring at ceilings or peeling labels off beer bottles!
I also cram fill my BBC I player. Make sure you do not have web connection when watching as the region monitor deletes the files! I now avoid doing any work on the plane when travelling unless its very urgent, all the mundane stuff I save for when landed to fill time.
Having an apartment to live in when in China means I have a huge amought of “cough” DVD’s to dive into + an abusive amount of alcohol.
Oh, and sometimes i skype the other half too haha. Seriously though, I plan to do this for another 3-4 years before toning it down and I am already looking for someone to replace me so I can kick back into semi retirement
Please god not the Archers, it strikes fear into my very soul (a long story from my childhood)