[hydroglide]

I have a 2007 Element AWD auto. It is was making a funny rattling noise sporadically(sounds like it is underneath between the rear wheels, like heat shield)... :15 seconds of noise then silent for a minute, then :20 of noise, then :20 quite, then some noise then maybe quite for minutes. It has also had a long time ticking noise up in front under the hood, sounds like the engine to me(like valve). I have asked the dealer service to look at it several times over the last few years. They always so all is good. Last spring they replaced the water pump bearing, battery, brakes under warranty (or some free service).
I was showing car to someone recently for a possible sale, it started with a new louder rattling-grinding noise. It also sounded like it was in the rear to me. I took in to the dealer and they looked. They told me I had some bungee cords in the back window making most of the noise (not true, the bungees were not making any noise and nothing changed when I removed them) and that up in front the A/C clutch bearing is starting to fail, they think. They wouldn't know for sure till they pulled it apart. They want $700 to do A/C clutch, Charge AC, replace serpentine... hopefully this will do it.
I have been asking them about the sound and it is on the record for over a year. The car went over 60K in July.
I have a bit of experience with cars. I restored a VW bus, rebuilt most myself. I also work around machine shops from time to time (but not auto). I am not afraid to role my sleeves up. I got the service manual, looks like a good deal of effort. To my understanding I am can't do my own AC coolant, so I will need to pay for that on top of parts. If they replace the whole AC I can do that for a little over $500 + charge. If they do it... $3000. The AC clutch, $350 for me on parts + the charge, or $700 and they do. Frustrated. In reading on the AC clutch it talked about the bushing on the clutch coming in different sizes, could that bushing just need replacing? (that's like a $2 part + a lot of labor)..

Is there a way I can verify in advance if it is the AC Compressor or Clutch... or some other part?
How urgent is this situation?
Can I avoid engaging those bearings to get buy more securely till repair?
Can I install a non-AC serpentine until repaired?