Some information about transport
From Seoul to Gangneung - about 2,5-3 hours by car/bus. Hope there will be a train also.
From PyeongChang to Gangneung - about 0,5 hours.
From Yangyang to Gangneung - about 40 minutes by car, long way by bus now.
From Donghae to Gangneung - about 45 minutes by bus.
For people who will live in Seoul. There is a very good transportation system there. A lot of maps, navigation, good subway and good buses. If you will no rent a car, choose some place near to the metrostation.
And about accomodation
Hotels in Gangneung: https://goo.gl/QMvvxA
In PyeongChang: https://goo.gl/f8Isce
In Yangyang: https://goo.gl/Fi6OX7
In Seoul: https://goo.gl/W6I72k
If it's comfort is important for you, I think, it's better to book hotel in Gangneung or Pyeongchang. If price is more important, book a hotel in Seoul. Sure, it's not so easy to sleep in bus for three hours on your way to Gangneung, but it's much-much more cheaper.
If now you don't know will you go or not, choose hotels with free cancellation. Your goal is to book it, because there are not so many rooms and beds already.
Also you can try to find something here. It's not so easy as on booking, but sometimes it has more rooms: https://goo.gl/2YmN3U
Someone could try to find free accomodation on Couchsurfing.com, but be careful, see previous opinions.
And as it was said by @DreamSkates , airbnb is good! The same system is https://goo.gl/To8W9n
Good luck and maybe see you
From Seoul to Gangneung - about 2,5-3 hours by car/bus. Hope there will be a train also.
From PyeongChang to Gangneung - about 0,5 hours.
From Yangyang to Gangneung - about 40 minutes by car, long way by bus now.
From Donghae to Gangneung - about 45 minutes by bus.
For people who will live in Seoul. There is a very good transportation system there. A lot of maps, navigation, good subway and good buses. If you will no rent a car, choose some place near to the metrostation.
And about accomodation
Hotels in Gangneung: https://goo.gl/QMvvxA
In PyeongChang: https://goo.gl/f8Isce
In Yangyang: https://goo.gl/Fi6OX7
In Seoul: https://goo.gl/W6I72k
If it's comfort is important for you, I think, it's better to book hotel in Gangneung or Pyeongchang. If price is more important, book a hotel in Seoul. Sure, it's not so easy to sleep in bus for three hours on your way to Gangneung, but it's much-much more cheaper.
If now you don't know will you go or not, choose hotels with free cancellation. Your goal is to book it, because there are not so many rooms and beds already.
Also you can try to find something here. It's not so easy as on booking, but sometimes it has more rooms: https://goo.gl/2YmN3U
Someone could try to find free accomodation on Couchsurfing.com, but be careful, see previous opinions.
And as it was said by @DreamSkates , airbnb is good! The same system is https://goo.gl/To8W9n
Good luck and maybe see you