I would say in 2020, online is the best option (coronavirus aside, still the best option lol)... First of all, you know everyone there is single and is wanting to find date - not the case in the library or the coffee shop. Secondly you can sort through profiles and find ones that you have things in common right away, before even talking to them (interests, hobbies, etc) so you will have conversation topics right off the bat. Also, you are open to talk to people from different communities and geographic regions so your options are very unlimited, compared to looking for dates at the gym or the beach...
Also, for someone like me (divorced mom in my 40s) it would be next to impossible to meet someone anywhere else - I don't go to school and wouldn't do that at work, so not many options left...
I would advice against going on IR specific sites, as there aren't as many members and usually not many in your area... just go on a general dating site, like match or eharmony and just try to get a date with whoever is on there. When I was online, I wasn't specifically looking for an IR relationship, it just happened that way, but if you are set on dating IR, you can do that too