There are some places I found while going back into the Soul Cairn that are still blocked off. For an example, the very first room you encounter on the path is blocked off with some bars, specifically, ones used for a jail cell. Even after completing Dawnguard, and a few game months passing, I return to the Soul Cairn and it's still blocked off. Is there some way of opening them that I am missing? Would really like to get past them as there are a few Jiub's little notes that are behind them, as well as some chest.

See those glowing blue orbs? Shoot 'em with something, (I use spells) and they open up the doors.

Took me a while too, personally.

Really? Wow, I cannot believe....

They should have at least made it more obvious! I thought those things were just for lighting. Thanks anyway, now I have to wonder around the Soul Cairn again opening these things.

Don't worry, I too had a facepalm moment as well...

The glowy balls reminded me of Zelda games, so I was like "Ohhh prolly have to shoot those."

Well,its obvious in my opinion - the first thing that i've done was casting a frost spell on them

A door close + a strange blue light = uh, i think is enough now,the poor jester is too tired

When i came to the first barred door with the glowing orbs there was a bow and arrows at the top of the stairs, and i wondered if you had to use them like you did in one of oblivion's dungeons (i don't remember the name its the one where you have to shoot an arrow through a hole in a statue) so i tried it and it worked.

Took me a while as well. It's so obvious now that it hurts though

You are told how to open them, by the trader near the wall I think.