Been searching all over and nobody seems to make this clear, can you visit Soul Cairn without joining the Vampires? Cause I heard the way to enter was to do certain quests in Castle Volkihar but how are we suppose to do that if where sided with Dawnguard?

It would seem really crappy if you had to side with the vampires to get in, I mean really its a whole plain of oblivion and a new area to explore!

All the Dawngaurd quests are basicly the same but from the DG pov. So yes, you still go to the soul carin.

Thank god, and thank you... why can't anyone just flat out say it, it not in any of the wiki's or reviews or anything... is nobody playing this from the dawnguard side of things? Seems like thats the reason why theres no information about non-vampires...

I've played 100 hours on all my characters as I tend to miss stuff the first time. And no problem.

serana gives you two options to enter the soul cairn ask her about both

You'll get some drawbacks for entering the soul cairn as a non-vampire. However, I'm told they're barely noticable.

You can play through without being a vampire just fine.

Slightly less stats and thats it so if your above lvl 30 or so it is not to bad but less than lvl 30 you may find it a good challenge.