Question: is the vdara connected to the cosmopolitan?
Answer: Yes, you can walk from Vdara to Cosmopolitan. The walk is a little bit tricky to describe, but it is the most direct and shortest route is to get from Vdara (and Aria's rear entrance) to Cosmopolitan. Exiting Vdara, make a left and continue just past the edge of building until you see a stairway to your left.