I agree with you about needing all of these repairs... I also took your advice and picked up my car from the dealership and took it to an independent shop I found on this site that was recommended.
Here is a breakdown from the estimate of the Nissan dealership in Northwest Las Vegas:
Replace radiator assembly $675 factory or $550 aftermarket
Flush cooling system $95
Perform idle relearn & reflash as necessary $95
Replace A/C low pressure hose $325
Replace 2 engine mounts (bushings bad) $625
Flush engine oil system $129
Flush automatic transmission fluid $129
After all of these repairs, the service writer told me the engine idle problem may not be repaired because I could have a problem with the throttle body. Wow! He NEVER mentioned that yesterday! How is it possible for me to spend close to $2000 and not have the problem repaired? He said because the temp of the engine was off, he could not diagnose it properly.
The independent shop tells me I do not need a new A/C low pressure hose which contradicts the dealership it is not leaking) and is installing a new radiator with hoses, fixing the A/C (not sure what the real problem is but they are fixing it) and repairing the idle speed problem all for $890
At this point, I don't know who to believe & I need my car in good running condition -- it's been 4 days without transportation. I've been dealing with these issues for months now and every person I take it to has a different opinion. Since I am female, maybe that is part of the problem. I do my research and try to understand these things, but it gets very frustrating! I gave in today and approved the repairs at the independent shop. Thanks for your help! I'll keep you posted.
Keep your fingers crossed.