Mountin o' mounts

Leading the Cavalry

This is a fairly easy achievement. The reward is the Albino Drake, it requires you to obtain and learn 50 mounts. One possible way to obtain 50 mounts would be:

• 32 standard mounts from the Horde / Alliance races
• 7 standard flying mounts from Shadowmoon Valley
• 5 cheap mounts from the Argent Tournament
• 6 PVP mounts bought with Mark of Honor

This list is debatable, if someone prefers daily quests over PVP, the Netherwing and the Sha'tari Skyguard are a good choice. If someone prefers getting this achievement done quickly instead of easily, farming Kurenai / Mag'har reputation is a good choice.

Mountain o' Mounts

This achievement is considerably harder than the previous, though with each patch it will get easier. The reward is a Red Dragonhawk for horde players and a Blue Dragonhawk for alliance players.

To complete this achievement, you need to obtain and learn 100 mounts. Ok, technically 99 because at 50 you receive the Albino Drake via mail for completing Leading the Cavalry. So to get those 99 mounts, some classes have an advantage because of class specific mounts, others have to work extra hard to overcome this.

This is the list of all the factions you will need gain exalted reputation with:

• Kirin Tor - equip the Tabard of Kirin Tor and do WotLK heroics and level 80 normal dungeons. Reputation gain ranges from 1000 to 3000 in these dungeons.
• Cenarion Expedition - do all their quests in Zangarmarsh, Blade's Edge Mountains, Hellfire Peninsula and Borean Tundra. After that a couple of Coilfang Reservoir: Steamvaults run will be required. It can be soloed easily, one run takes 20 minutes and gives about 2000 reputation if you turn in the Coilfang Armaments. It will take roughly 10 clears to reach exalted.
• The Sons of Hodir - daily quests in The Storm Peaks for 27 days
• Netherwing - daily quests in Shadowmoon Valley for 29 days, but now that almost noone plays in SMV, it can be extremely easy to farm Netherwing Eggs as well. There's a good video with a path you can patrol to find eggs on Youtube
• Sha'tari Skyguard - daily quests in Terokkar Forest and Blade's Edge Mountains for 37 days, but with summonning Terokk and the minibosses, you can gain 2500 reputation in 25 minutes
• Wyrmrest Accord - equip the Tabard of Wyrmrest Accord and do WotLK heroics and level 80 normal dungeons
• Mag'har / Kurenai - farm Obsidian Warbeads in Nagrand. Laughing Skull Ruins and the Warmaul Hill are a good place. The whole ordeal shouldn't take more than a day
• Horde / Alliance - all the starting zones and the Argent Tournament's daily quests

It is also recommended to raise The Oracles to revered because the Mysterious Egg (available at their Quartermaster) requires no extra work and it has a chance to drop the mount once every 7 days.

In addition to these factions, you will need:

• a considerable amount of gold - over 50000g
• 525 Champion's Seal - 5 seals a day or on average 6 if you choose the Champion's Purses instead of the Champion's Writ as questrewards. Until you no longer need reputation for any of the Horde factions, you should choose the Writs.
• 300 Stone Keeper's Shard - 40 shards every week with the weekly WG quests, though you can do heroic dungeons (for the Kirin Tor and Wyrmrest Accord reputation you have to do that anyway) and obtain extra Shards while your faction controls the Wintergrasp.
• 200 Emblem of Heroism - the heroic daily quest rewards 2, raids drop a lot more (and don't forget that Emblem of Valor and Emblem of Conquest can be exchanged 1:1)
• 200 AV Mark of Honor
• 150 WSG Mark of Honor
• 150 AB Mark of Honor
• 170 Halaa Battle Token - these can be generated by partying up with a Warlock who left all his gear in the bank, going to Halaa when it is controlled by your faction, going to the Spirit Healer and having the warlock constantly kill himself with Hellfire and instantly resurrecting.
• 35 Halaa Research Token - very painful to farm them thanks to the 8% droprate, but you should get 20% of the required 350 Oshu'hun Crystal Powder Samples while farming the Kurenai / Mag'har reputation, after that Sunspring Post seems like a good way to finish the work.

If you have all of these funds and have the above factions completed, you can buy 86 mounts. You also got the Albino Drake, so 87. You can buy the Chopper, that's the 88th. The last 12 will get harder. You will need to work your way through a bunch of achievements and get your hands on random drop mounts as well, there's no way around them.

20 minute CoT: Stratholme run, Glory of the Ulduar Raider, For the Horde / For the Alliance, 10 man Sartharion hard mode should be easy to get for anyone. The more of the Achievement mounts you can obtain the better, but sadly, it still won't be enough.

There are a bunch of random drop mounts that are easy to get, despite being... random.

• the 4 AQ mounts can be obtained by pulling the first 4-pack in AQ40, killing 3 of them, looting them for the mounts and running out of the instance. When you go back in, the pack is reset and you can kill 3 of them again for a chance to drop the mounts.
• Kael'thas has a 2% chance to drop the white chicken and by now MGT can be soloed by a lot of classes, if you're not one of them, ask a friend to help out with the tougher trashpacks
• even though the ZG mounts have a low chance to drop, there's 2 of them and it takes only a half an hour to kill Bloodlord Mandokir and High Priest Thekal every 3 days (and you can skip every other trashmob and boss in the instance). Again, it can be soloed by a lot of classes, if you're not one of them, ask a friend to help.
• both bosses in the Vault of Archavon have a chance to drop the Grand Black War Mammoth in the 10 and 25 man version as well. If you're in Wintergrasp for the weekly quests (which you are doing anyway because you need 300 Stone Keeper's Shards) kill them with as few players as possible, it takes almost no time.
• the first couple of weeks you probably won't have free daily quests, but as soon as you do, you should start doing the Brunnhildar daily quests in The Storm Peaks for a chance to get the White Polar Bear

If at this point you still don't have 100 mounts, the next easiest would be to drop one of your professions and raise Tailoring for the 2 flying carpets and after drop it for Engineering to craft the 2 helicopters. You probably don't have any trouble raising a lot of money for chopper and the 40000 golds worth of other mounts, so these are good choices.

After that, you should head straight to Stratholme for the Deathcharger's Reins.

Good luck!