* As for , it's always used with . I don't know when to use .
* As for , is used in the same way as ("go to "), ("come to "), ("head to "), ("send (something) to "), etc. It's the primary particle that marks a destination.
That said, you cannot always expect a logical answer for this kind of question. You may find this interesting:
vs. - Why not the same particle?
* * *
(By the way, whenever I see "to drop _by_ ", I can't help feeling it's counter-intuitive...)