I hope you haven't started yet. Compressors normally don't go bad, just the clutch. The evaporator replacement is very lengthy, as the entire dash has to be removed - down to the firewall and the car will not be drivable during the process. Winter is coming, so you might want to wait until spring and look around on the web for lots of pics.
www.volvospeed.com and
www.matthewsvolvosite.com/index.php


The above are good sites to explore for pictures. For "normal" AC fixes, remember that local AC garages can also work on your car. Like professional shimming of the clutch, or replacing the receiver/dryer bottle which can get clogged from repeated charging.



There is also an easy fix for the compressor clutch using bread clips and a little glue on volvospeed. But that means the clutch gap is too large and once the engine gets warm, the compressor fails to engage. You have to figure out what your specific problems are.

The crunch door hinge is an easy fix if it is just a broken door stop strap:
http://volvospeed.com/Repair/850_door_hinge.html

A little harder if the connection to the A pillor has broken:
http://volvospeed.com/Repair/hinge.php
OR
http://au.geocities.com/ozbrick850/door-stay_fix.html

I hope the above supplies some good hints.

Klaus
--
Mistakes make us learn. Beer is for a job well done.