After finishing leveling in the Wotlk zones, you will move on to Cataclysm zones. The Cataclysm zones are scattered all over Kalimdor and the Eastern Kingdoms, So you will have to travel a bit. Your capitol city will have portals to all the zones though.
Mount Hyjal Level 80-82
The first zone you should hit up is Mount Hyjal. The zone is fairly large with some long quest lines and a lot of quests that will level you up to around level 82 pretty fast. Questing here can also be combined with questing in Vashj’ir if you want to switch it up a bit.
Vashj’ir Level 80-82
Vashj’ir is another 80 – 82 zone. I would recommend going to Mount Hyjal first as questing and leveling is a bit faster and easier there. Combining the two zones is also a viable choice.
Deepholm Level 82-83
At around level 82 after finishing up in Vashj’ir and Mount Hyjal you should move on to Deepholm. The zone is located underground and is filled with caves and tunnels. Traveling around can be a bit tedious but leveling is generally fast.
Uldum Level 83-84
At level 83 move on to Uldum. Uldum is a giant desert in Southern Kalimdor. You will spend some time traveling around the zone but there are a lot of quests.
Twilight Highlands Level 84-85
Twilight Highlands have some of the best and different quests in the game. Leveling from 84 – 85 doesn’t take long and if you haven’t done the quests to many times before they are really fun.
Throne of the Tides Level 80-82
Blackrock Caverns Level 80-82
The Stonecore Level 81-84
Vortex Pinnacle Level 81-84
Lost City of the Tol’vir Level 83
Halls of Origination Level 83
Grim Batol Level 84