The best thing you can do is conduct a little door knocking around the property you are considering and talk to the residents on both sides of your prospective home.
Nobody can give you an answer better than the people that already live there and people in Tahoe are generally great about talking to their neighbors.
The quietest area I lived was up off of North Benjamin on Kingsbury grade. Never had any issues with noise there at all. Well, except for snow plows. :)
Zephyr Heights is heavily populated with locals and owner occupied homes. If you are interested in the Zephyr Cove area I would be happy to send you some information about each neighborhood in the area. If you are send me an email to email@example.com. I will have some reports generated for you to answer all of your questions. I am a Zephyr Cove native so I know the area well. I look forward to hearing from you soon.
(775) 850-5900 office