I worked in dealerships for a long time. The doc fee does seem high, but I would guess that the other dealers in your area charge the same amount (or nearly the same). That's usually how that sort of thing works.
If I were in your shoes, my only concern would be that the dealer either 1) sells the truck to someone else or 2) loses the incentives they need to guarantee your price.
Considering how crazy things are right now, neither one of those things is likely to happen. Still, it's always possible.
Might I suggest that you give the dealership a "hold check" for $5k and do the deal now? That way you don't have to worry about this deal changing and/or blowing up.
As for "tricks", most of the tricks are in the finance and insurance office. Here's a good list of tips for dealing with the F&I guy:
Financing at your local dealership: Tips and Tricks For Saving Money | Accurate Auto Advice