I am currently lvling a new character and this will be the 2nd time i do the Dawngaurd side of the questline, i dont want to be a vampire. This character is a nightblade so i do alot of stealth and do not really like having followers. My question is, can you do the DG questline without having that vampire girl, forget her name, tag along?
I seem to remember that she was important to the progression of the questline, almost like i could not have moved forward with certain quest without her being with me. Is this true?
I would really like to solo it but with the same outcome.

One more thing and this is a bit off topic. I just recently noticed that since i installed HF, couriers no longer approach me at random times throughout the game. I just randomly find letters in my inventory as if they approached me. Not a big deal i guess since i am still getting the quest but i was just curious if anyone else is having this issue.

-Thanks

I believe that most of the time you can just tell her to wait somewhere and you can progress on y our own. But when going to Castle Volkihar's courtyard, or visiting the Soul Cairn for example she definitely needs to accompany you.

Yeah, that is what i thought. Once i start the DG questline i will just do only that till its end. I dont want to have anyone with me as i finish the TG and DB questlines.
As far as having them wait goes. I dont know if i just have a bug or what but it seems like everytime i tell a follower to wait somewhere they will end up loading in with me whenever I zone. That is probably the way it is suppose to be... i dont know.

Thanks for your response.

You have to have Serana for Chasing Echoes (she has the key to the undercroft), Beyond Death (she needs to soul trap you or turn you into a vampire), Touching the Sky (she is needed for the final boss fight) and Kindred Judgement (she needs to confront her father). You don't need her for Prophet. I am not sure if you need her for the Ancestor Glade thing.