According to Gamespot's hands-on preview, Link pulls a Zelda II with how the game starts. Decided to take a nap for 100 years before waking up.
In regards to the game world's size, it is around 12 times larger than Twilight Princess in terms of scope and the stuff being shown at E3 is only around 1% of the entire map.
Also confirmed there are no collectable hearts in the game and instead need to get food or scavenge around for items to refill the health bar.
http://www.gamespot.com/articles/the.../1100-6440864/
Other reports from E3 hinted at there being over 100 shrines or mini-dungeons in the game in terms of possible side quest stuff.