I've lived, travelled and regularly go on holiday solo to Thailand. It is very safe, or as safe as anywhere if you're sensible and careful. People are friendly, accommodating to foreigners (when in tourist location especially) and if you try to learn Thai you will make so many friends. * I'm Not retired fyi *
If you go into your local library, not only can you use the computers there, but the staff are usually on hand to help you with such things, or provide you with a session for navigating/ learning yourself 👍🏽
Teaching English is the easiest thing. Lots of work about, but need proper qualifications to make decent money, but if that's not an issue, then you can get (really bad paying) teaching roles.
I've lived, worked, holidayed in Thailand for over 18 years, and if you throw yourself in, there's plenty to do. Happy if you want to share my info with your wife if she has questions. Can't guarantee I'll be able to help, but certainly experienced as a woman 'expat' / traveller 😄🙏🏽