The quest chain to completely open up the Sons of Hodir rep grind is long. Really, really long. It's long in the good way, though. It's epic, and part of the chain is quite possibly one of the most fun quests in Wrath, and is as close to God of War as you're going to get in WoW. 'God of War in WoW!?' is what you're probably thinking. My answer to that? Yes. It's freaking awesome.
I hope you're sitting down, because I'm about to list the entire questline for you. The very first quest can be picked up at level 77 in K3, the Goblin town that's sitting right inside the entrance to Storm Peaks from the south. From there, just go where the wind (quest) takes you.
Yeah. It's absurd, isn't it? Trust me when I say it's awesome and completely worth it, though. If you want to dodge spoilers, don't click on the quests themselves, just use the list as a reference if you get stuck and don't know which quest you should be doing next to progress.
If you get to a point where a certain quest is unavailable, it's possible that you're just a little rep short of Friendly with the Sons of Hodir at the point where it becomes important, and if that's the case there's an easy solution. Before this becomes important, the daily quest Hot and Cold opens up within Dun Niffelem at an anvil on the upper level. Do that quest, and it will push you over to Friendly and you can continue the chain. That didn't happen to me, but it has been reported, and doing that quest seems to be the 'fix.'
The Sons of Hodir don't have a tabard that you can wear to Champion their cause in dungeons and Heroics, so reputation gains are going to be purely through daily quests and drops/looted items. After doing the quest chain above, you'll be well into friendly with the Sons. At each reputation level, a new daily quest or two opens up, similar to how the Netherwing faction worked in The Burning Crusade.
Unless you get amazingly lucky with finding Everfrost Chips for the Everfrost repeatable, this grind will take you a little under a month to complete. Yeah, that's pretty harsh, but look on the bright side. The money from these dailies is really, really good. You do most of them in the same little areas, and Thrusting Hodir's Spear is regarded as one of the best daily quests ever. It's another of those God of War meets WoW moments.
To inspire you to get started on this reputation, I'll leave you with a video we posted awhile back from a friend of mine. The video is of the Drakkensryd, one of the quests in this very long chain. Have fun on your adventures!
Arthas awaits and so do your questions. Find the answers you've been looking for that will help you with your journey into Northrend and to level 80 with Wrath 101.