Well, it's easy enough to check the fan: wait til you hear it kick on, then look up under the bumper to see if it's spinning. (stop all forward motion of the car first though

)
All the parts of the AC system, including what's up under the dash (which BTW will not affect the heating system as they are two seperate units) is a substantial amount of weight. (AC compresor alone has to push 20+ pounds and that fan is a good 5)
Still, removing it all doesn't really do anything to get you more room to work on things in the engine bay, but it's one less belt to mess with, and you can get behind the glovebox quite a bit easier. (like say you've got to work on those triple gauges)