For starters, if that's the original battery, it needs to get load tested. It may have voltage, but
not enough amperage to get things going. Five years is pretty much max life on batteries in
these trucks, and they are really picky about their voltage and amperage levels.
As soon as you can get a meter, recheck fuses. Visual checks can sometimes overlook
conditions like bad connections in the fuse block itself, as well as hairline breaks in older
fuses. You can check voltages at the battery as well, which will tell you if you've got a
bad cell, but won't tell you if there's an amperage problem (you can have 12+ volts at the
battery but still not have enough current to run the vehicle).
Removing the key can usually be done through a small access hole in the underside of the
steering column, near the keyway. You should be able to push a Phillips screwdriver in the hole
and hit the small release button by the keyway, turn the key and pull it out.
Stuck key is a sign of no power, but could also be a problem with the shift interlock system.
It's supposed to prevent removal of the key while in gear. If, for some reason, your truck thinks
it's still in gear, it will not start, and won't let you take the key out.
Also, make sure the small ground wire from the negative battery cable is still connected to
the fender wall. If it got disturbed while you were working on things, that missing ground can
cause a lot of different (flaky) issues.
The fact that it ran for a few minutes then died is also somewhat indicative of a problem with the security
system. There are some models that are designed to allow the vehicle to run for a short period of
time before killing the fuel pump circuit or starter. Are you seeing anything on your instrument panel,
like the "Security" light, when you try to start it? That doesn't explain the no-start behavior subsequently,
but maybe there's a relearn procedure for that security system that needs to be performed after the disconnect.
There have also been cases where aftermarket systems have prevented the vehicle from starting thanks
to bad connections or blown inline fuses, so you may have to go digging for things like that.
Good Luck!
Chris