If you lack opportunities to go abroad due to a lack of social circle what other options are available?
Volunteering is one option but I wouldn't be able to do this independently.
How about going to an adult autism summer camp?
There quite a few actually, if you google for it. Many in the US and Canada.
Here's one I found for ages 18-45 and up, www.campbarnabas.org/.../
Other options would be to study abroad for a graduate degree, or to find a job abroad, or if your work involves opportunities to go to international conferences...
There's lots of single travel companies specialising in taking groups away.
Do you want to be with NTs or NDs?
Are you ok with the travelling, airports, foreign environments?
Are you looking for a weekend, a holiday or a longer experience?