1 'Know of' is a bit less specific than 'know. Examples:
I know of a place - somewhere out on the Oxford Road I think.
I know a place, on the right just before the turning to Wallingford.
2 In many contexts, adding 'there' at the end doesn't change the meaning, but in some cases you may want to make the limits of the journey more explicit: 'I can take you there, but I'm going on to my mother's - so you'll have to make your own way home'