Be sure to use universal joints on both ends of the pump drive shaft, and make the crossmember that supports the pump plenty strong! A simple piece of flat bar pivoted in the middle, and attached to a piece of round stock with clevises on both ends is all you'll need to engage/disengage the PTO. Run it through the floorboards near the parking brake, with another handle to the hydraulic valve for the dump bed.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!