Um,
A LOT has changed since then. Hunters in particular since they no longer use mana and don't have any of the goofy melee abilities anymore. Not to mention that ammo is gone, as well as the pet happiness system, among other changes (mostly improvements.)
Honestly my advice would just be to reroll and learn things fresh by playing, especially if your old server is dead. 1-70 hardly takes any time nowadays, even without XP bonuses it would be pretty fast. Make a new hunter if that's what you think you still want to play and level it to at least 20 or so before even touching your old character. Otherwise you can't go wrong with a completely new class. If you decide to stick with your hunter after getting a feel for things (or getting a new character to 68), you'll want to go to either Orgrimmar/Undercity or Stormwind/Darnassus(I think) and take a zeppelin or boat respectively to either Borean Tundra or Howling Fjord in Northrend to continue leveling there. Personally I enjoy Howling Fjord more, so that would be Undercity (zeppelin tower s at Brill) or Stormwind (the harbor.) Ask the NPCs to find out which boat/zeppelin is the right one to take if you're not sure.
Talents and specializations have been completely revamped, spells have changed, with more new abilities of course, among various other changes to stats and other things, like spell resistances being removed.
This Page provides a short overview of some things, but is hardly comprehensive. If you want more gritty detail, I would read the patch notes for Cataclysm launch, and all the Mists of Pandaria patch notes.