I recommend Fairbanks, but I'm biased. I've lived here for 35 years and love it. March is possibly the best month of the year. There's lots of sunlight, the days are long, and the temperature is usually above zero. Some of the events taking place during the second half of March are the Arctic Winter Games (3/15-22), the Ice Art Championship, the Limited North American Championship Sled Dog race (3/15), the Open North American Championship Sled Dog Race, and the Sonot Kkaazoot Cross Country Ski Race (3/29). Other things to do include taking a soak at Chena Hot Springs, viewing the aurora, walking with reindeer, visiting the Museum of the North at the university, and taking a dog sled tour. I'd be glad to answer questions if you have any.