Can you return as you please back to the new area afterwards. Also a yes/no on whether or not to get would be helpful
Yes. I havent gotten that far, but I've read but according to what I've read on the fallout site all the DLC except Dead Money will still be accessible after the quests have been completed.
What about upping the level cap? Can we go over 35 now?
Yes the cap level has also been raised by 5
once completed you can travel to HH as and when you want, and yes another 5 levels, and some new perks!!
Yes you can. And yes the cap was raised to 40. By the time the last DLC comes out we will be able to hit 50! My stats will be looking sharp!