I’m looking at buying a 1995 Nissan Quest that’s been sitting in a
parking lot at work for about a year.  The van had nothing wrong with
it when it was last driven, but now it won’t start.  I checked all the
fluid levels before trying to start it and swapped out the battery as
I’m pretty sure it’s dead after sitting that long.  The van tries to
start, but won’t crank over.  The starter turns the engine, none of
the fuses look blown, and all the electronics inside are working (dash
lights, power windows/locks, radio, etc).  It’s acting like there’s no
gas, but I put a couple gallons in after swapping the battery out.

I was thinking that because it has been sitting for so long that it
may need manually primed, but I have no idea how to go about doing
that...

Any suggestions?