Iceland for 2.5 days? Please recommend aurora trips, hikes and anything else. [US]

Hey Travelers,

I'm going to Reykjavik for 2.5 days and want to make every second count even if I can't sleep a single moment. I'm going in April. Usually I begin with lonely planet to get some suggestions but it seems like Iceland's recommendations feel unusually generic. If you can't make recommendations for a specific, how about for some great resources from other millennials for top notch travel tips?

Thanks!