I'd guess that the AC compressor clutch circuit is the culprit. There's a
relay that switches the main current. Buy a bag of fuses and disconnect the
clutch  (trace the wire in the engine bay). See if firing the clutch relay
still blows the fuse.

Side issue: If the AC is not pressurized, be aware this car is R12 based.
Its cheaper in the long run to get it converted to R143a than find someone
who can supply and install R12.  If the AC is still partially pressurized,
get a can of durakool R12 compatible and see if it holds up.

SD

If the fuses blows immediately, then there is a direct short to ground
somewhere in the affected circuit.  You will need a wiring diagram and a
multi-meter to diagnose the problem.  Start by checking any aftermarket
accessories or parts than have been tapped into the circuit, like remote
starters, security systems, lights, and audio systems.  Then check the power
window master switch and circuit, then the AC circuit.

If it takes a while before the fuse blows, then there is high load
somewhere.  You have to determine which item makes the fuse blow, i.e.,
turning on the AC or using a power window and check the operation of the
load on the circuit.