I was there in July (took a picture of the sun looking like it was 4:00 in the afternoon...at midnight) and occupied 24 hours easily (although at a relaxed pace). Lots of walking around, borrowed a friend's truck and drove up to the northern end of the road (unfortunately, didn't make it out to the point itself , ate a couple expensive but decent meals, wandered through the heritage center and--almost more interesting--the grocery store (to ogle at the insane prices)...definitely would recommend it as a memorable trip. You might not enjoy the walking around part as much in March, though.