The other thing is, when we discuss "changing your life" as if that would almost definitely mean or at least include travel, we're kind of limiting it. Travel is great -- attitude changing and enriching and enjoyable and all of those things. But most of us can only do it a few weeks a year at most. Plus, Jeff has done a fair amount of it, even if he can't for now. I'm lucky to get a trip or two a year, and in recent years I've been lucky enough to get most of them paid for by professional organizations. Recently, Brokies on either coast have invited me to visit, but I don't think I can anytime soon.
But anyway! I think long-term significant life changing would most often entail getting extremely involved in another time-consuming social or educational thing. Like Lee's permaculture, for example. Obviously that particular thing probably wouldn't work for you, Jeff, but I mean something like that -- where you're really invested, engaged, interested, meeting new people, have a steady schedule of activities, etc. I'm not sure what it would be for you, but I feel like it should be something you're fairly deeply engaged in.
A coworker wanted to learn French because her daughter was living in Paris. So she started taking classes and she organized a French club at work. I was in it, but some of the members had lived in France whereas my French is rusty high-school level. I felt like I needed subtitles. So that probably wouldn't be the best thing for me -- although I will say going to the sessions was like taking my brain to the gym and it was interesting to see my coworker get increasingly fluent as weeks went on). She made friends in the French learning/speaking community. has since retired, but I bet she's still doing French stuff. And last time I saw her, a year or two after she retired, she looked great: happy, healthy, vibrant.