I would advice avoiding Ring of Blood in nagrand unless you hve some geared 80 backing you up. Things rarely goes smoothly there and most of the time you have a ****load of 80 killing each other, while guys doing quests suffer from collateral damage.
As horde I did
Starting zone
Ghostlands
South Barrens
1k Needles
Dustwallow
Feralas
Hinterlands
Plaguelands
Should be 58 by then and make way for Hellfire
I made my first 80 a DK, after that I just boost alts through dungeons. You have good gear heading into Hellfire that way and imo its quicker. Mind you I have a travelers mammoth so selling and hauling around the alt is a breeze, but for anyone that wants to try heres how I do it.
Level till they are either level 9 and do RFC or quest till youre 15 and skip RFC go straight for Wailing Caverns (the quests are worth picking up here since theyre right there and you get a quest item at the end thats in the same area.)
-lvl22 go do RFK all the way through (escort quest). I usually do 2 more full clears, even the mobs you kill on the escort and then head out.
-lvl30 you can jump across the road to RFD or head to SM, can easily hit 40-42 with SM and Cath takes only a few pulls to clear and the exp is a few levels a clear until about 37 or 38 then its 1 level a clear, still faster than doing 4-5quests to get a level at that point.
-lvl42 head to ZF, up to you how long you want to stay, I did 1 full clear and then after that I cleared trash around the start for a few resets until was ready to move on at about lvl50.
-lvl50 head on over to Strat, 2 1/2 clears gets me to 58