Old thread but like to add that I am a bit of an EV nut. 72 or 96 volts is not enough for a truck. First on-road EV I had was a converted S-10 truck. Started out at 120 volts, I eventually crammed in more batteries, tried 176 volts, then ran 132 volts with a bigger controller (1000 amp till I blew and I went to 600amp). And I loved that truck - great for running around town, including building half a house - hauling wood, mulch, gravel, scafolding, etc. The bigger controller made a huge difference to getting the low end torque needed to get it moving.
Then "upgraded" to one of the few factory built S-10 electrics (same drive train as the EV1 as in Who Killed The Electric Car). Nice truck when it worked, but way too finicky with all the computer systems always throwing error codes. Then came a used Solectria Force. Currently needs rebuilding, so missing my on-road EV fix.
Using a van will reduce your range. It all about the ratio of battery weight to total weight. If doing basic lead acid batteries, aim for at least 1/3 of the weight in batteries, better if can manage 50%. To get an idea of how a particular configuration will perform, there is an on-line EV calculator:
It is getting old at this point so doesn't list any of the newer controllers etc. This one
appears to be a somewhat newer tool, but I haven't used it.