I wonder why people don't try following the rules of any RPG:
"If you think you are lost, think twice. Try to talk with everyone, and try to go everywhere you can. Sooner or later you'll find the correct place or people to proceed further"
(in fact this is told in the Help Menu of the Pokemon games... wonder why don't you follow it?)
In your case, you've gotten your surfing Lapras, what would you do? Start surfing... Where? Everywhere you can, from east to west, from north to south. In the end you'll find your next destination. Of course, you may end up in a lot of places that don't seem to have any apparent importance, if so, just backtrack and look for other places.
I don't like being explicit, maybe if you remember this words it may increase your skills as an RPG gamer ;)