i did an away rotation at Wash U last year called "Clinical Aspects of Aging and Dementia". it was excellent, and wash u is a top neurology program. on the interview trail, i met a person who really enjoyed the visiting rotation at columbia (i think she was at harlem hospital). a friend of mine did a visiting rotation at northwestern in behavioral neurology (working w/ mesulum) and he enjoyed that as well
it kind of depends on where you intend to do residency. if you want to go to a specific region, i would pick themost well known two or three neuro programs in that area and apply to them for aways electives (you don't need to do that many rotations, but just to cover your bases in case a place can't schedule you).
if you want to go to the a "top ten neuro program", i would apply to three or four of these top ten programs and see what works out.
if you want to go to a specific school: apply for different roations at that school
and letters: try to schedule it for july or august if you intend to get a letter from that rotation (you should aim to have your sfmatch application in by the second week of september)
hope this helps, good luck
