I think you could do this on legendary from the get go. You have conjuration, illusion, and sneak as skills. I had a similar build, except bound bow and not a vampire, got to level 32 on legendary, no-crafting, before my laptop's video care fizzled out on me. I would have kept playing him otherwise. Picked up Jenassa from the beginning and like you said, you gotta pick your battles. :) Very carefully.

Awesome build, definitely got my +1 (Albeit, you had it the moment you said no crafting, hehe)

Sir, take my +1.

I've played around 7,237 hours of Skyrim, and this is the best build I've ever played. I'm not allowed to purchase DLCs, sadly, but I found that this build still works like a charm, even without DB or DG.

I made a couple of changes, however. I sided along with the Dark Brotherhood, to give me something else to do (no DLCs gets boring after a while xD) and also for the Initiate, because I'm not a master with the build. 

It was a pain doing the Civil War, but I managed to crawl my way out of it. I'm considering doing the Thieves Guild, but I'm not exactly sure.

Thanks for the build ^^.

Happened to see this pop up on the recent activity and hadn't seen it before.  Very cool looking build. 

As a small add, if playing on PC, there is a mod that now allows you to join DG as a vampire to circumvent that issue with Isran should you wish to do so.

I've contacted HeroicX about making a video on this build, I hope you don't mind. He said that the build looked very interesting, and that he would contact you.

I just wanted to see some gameplay of the final build :3.

Amazing build. :)