I personally think that if you're good at something you should never do it for free, charity work notwithstanding of course. In your case, I don't really understand your reasoning/correlation between wanting to travel and offering your AWS skills free of charge. You can always find early stage startups that are looking for someone to setup their system on AWS, and willing to pay for it, in any of the cities that you've listed. They might want a one-time job (think freelance).
Why wouldn't you offer a paid service?