Storybrook Vale

So I have EI but I haven't finished it story-wise. I've had it a long time but I purposely don't run through storylines for games like this. I DESPISE having to wait for updates and releases so I take my time so that I never run out of stuff to do. I want Storybrook Vale for the new content and everything but I'm jw if I could do anything with it's storyline until I've finished EI..? I still have quests in the base game, I'm finished with the main story but I still have plenty of character quests and 2 characters to unlock so I've got stuff to do, and then with EI I'm in part 2 I believe. So I read that SV picks up after EI is done, so that's basically what I'm wondering. Could I have storylines in both EI and SV that I'm working on or would I just get the content and biomes but storyline wouldn't start until I finished part 3 of EI??