Well, I presume you would not have had anything to eat at 7.00pm, so why not go to a wine bar or somewhere nice and casual for a bite to eat and a chat to get to know each other and then decide from there. Better than walking or driving around trying to think of something to do.
No you don't have to invite him in just because he knows your landlady. Just be ready and waiting, smile sweetly and shut the door firmly behind you as you leave.
Good luck! Don't expect too much and then you can't be disappointed. Just remember you a meeting a new person, not necessarily a prospectie boyfriend, just someone new to get to know.
Oh, you are making me remember how great it was to be young!