A few simple answers:
1) FAQ Birdwatchers Digest:
"...Still others, like geese and swans, make their migrations in family groups, led always by an older bird that has made the flight before. There is still much to learn, however, about how birds make such long flights and find precisely the right spot."
2) The Bird Lady
"..The Bird Lady:
Geese are among the few groups of birds that can migrate by day or by night."
3)BWB-ASF Library: Bird Migration Facts
4) PNNL: Science & Engineering - Shurb-Steppe Series: What About Canada Geese?
5)Geese Are Carb-Loading: Green Meditations Blog