I understand what ur saying, an the answer us yes u can run it to ur main battery in van, u could either just use a switch to turn it on or off or use a controller. I run from main battery as do a few miles
I have 2 pump set up but only use the one, second is set up as spare but gets used very really if I have 2 of us on the poles, or if I fill up with tap water I will run it through second pump di bottle back into tank, these pumps are bolted into bulk head as low down as pos.
Mine is diy set up and I use the space behind bottom of tank ( against bulk head ) were I have my pumps, wires are run from battery which is in the floor in front of passenger seats ( small cut into rubber floor ) for wires to run through, and drilled a few holes in bulk head for wires to go through.