The experience is as good as can possibly be.

You don't know how good "as good as can possibly be" is yet.

I want to continue to be someone who thinks things and does stuff, even at a cost in happiness.

But surely the cost in happiness that you're willing to accept isn't infinite. For example, presumably you're not willing to be tortured for a year in exchange for a year of thinking and doing stuff. Someone who has never experienced much pain might think that torture is no big deal, and accept this exchange, but he would be mistaken, right?

How do you know you're not similarly mistaken about wireheading?