Guam is so far away from Hawaii it's not even funny.
True, but that's not necessarily a bar, unless the Guamanians think it is.
There's a twenty hour difference between Guam and Hawaii. If they were all one state, the polls in Guam would be closed and counted even before the polls in Hawaii.
Or they would vote the next day, in which case there would be only a four-hour difference. Not hard. I'm sure Congress would waive the ordinary requirement for federal offices (as they would pretty much have to if Guam were a state itself anyway), and state law is state law and easy to change.