If you become a vampire early in the game, why would you ever want to join a newly forming group of vampire hunters?  Yet, this is the only path Bethesda has given to progressing the Dawnguard quest line.  For role playing purposes, it is quite frustrating.  How could you know that meeting Isran would be the only way to become a vampire lord?  This mod corrects this potential plot hole by allowing you to receive a letter from the Volkihar vampires shortly after the Dawnguard quest appears in your journal, so that you can go directly to Dimhollow, free Serana and become a vampire lord!  You will only receive the letter if you are a vampire when Dawnguard begins (level 10+ upon hearing a rumour from a guard or meeting Durak).  If you are not a vampire at this point, or choose to visit Fort Dawnguard anyway, no significant changes will appear in your game (unless you give yourself the letter via console).  If you never met Isran, you will not be able to tell Serana that Isran sent you, or that the Dawnguard would want you to kill her.  And if you are a vampire, you will no longer have to sound like a moron and tell Harkon that you will accept his gift and become a vampire, or that you don't want to become a vampire; rather, you can qualify it and accept or reject becoming a Volkihar vampire.

Likely incompatible with other mods which alter the quests DLC1VQ01MiscObjective ("Dawnguard"), DLC1VQ01 ("Awakening") and DLC1VQ01RNPC.  UPDATE: After investigating further, it seems that mods that delay the start of Dawnguard (e.g., Timing Is Everything) ARE compatible, as they change a value and not the quest. Vampire attacks are controlled by a separate quest, and mods which alter such attacks should be compatible.

VER 1.01  Corrects a typo and opens Ruunvald to Volkihar vampires.