Go to the top right area of Area 1 of the Safari Zone. In this area is a Rest House. In the area over top the Rest House is a patch of grass that in a way resembles a leaping animal. This area of grass I've found has the largest percent chance of encountering a Kangaskhan. Others have confirmed this. Yesterday I encountered three within just 10 minutes. When you encounter one, don't waste your time with all those bait/rock throwing combinations BS, just keep throwing Safari Balls. If it flees, keep searching in that area again until you encounter another one. Rinse and repeat. Using this technique I caught some three Kangaskhans for the first time yesterday.