There are advantages to each of those neighborhoods. One, Gardner Mountain is close to the public beaches and bike trails, about 15 min. to the downtown and Heavenly Ski Resort. Al Tahoe is walking distance to the lake and about 10 min. to downtown and skiing. Both are great neighborhoods! Gardner Mountain typically offers a larger lot and you feel like you are more in the woods.

How much is the investment required for AI Tahoe vacation rental and what is ROI after Mortgage payment and Management fees . Any Good References ?

Depends on if you are looking for Vacation Rental, Ski Lease, or Long Term Rental? Al Tahoe is better for Ski Lease and Vacation Rental's, and Gardner Mountain is better for Long Term Rentals.