Can't comment on how long you should wait before suggesting a meeting but you should assume the worst when considering where to meet, and make appropriate preparations. I would suggest somewhere very public, and preferably somewhere you are known, either that or have somebody you know be there when he arrives. Meet him (I'm making a big assumption here) there - don't tell him how to recognise you - find out how to recognise him so you can do a runner if you don't like what you see! Tell someone close everything you know - email address, how he contacted you etc. Don't go anywhere else with him first date, and make your own way home. Good luck!