I've managed fortune 1000 campaigns.
Charge what they can afford. Period.
I'd say no less than 10-20K a month.
Another thing to keep in mind, is that the communication is going to be far more consistent (obviously).
When I was managing a large, corporate account, communication was almost daily, and we had weekly calls every Friday.
Depending on how savvy they are, they're going to want a publishing schedule. They may also require everything you publish to be ran past their PR team, if they have one.
Then again, you'll be working with a manufacturer- I was working with a marketing company. They may be clueless, and your communication may be minimal. I have no clue. But that would be sweet.
In short, don't be afraid to quote them a substantial number. If you don't, they won't take you seriously.
GL bro.