If you are now planning on 2 nights/3 days then the next logical stop would be in Death valley, Panamint springs and Stovepipe wells have lodging and would fit around your travel time, including the onward journey to Vegas. I would recommend you book in advance as it is limited and October is a nice time to visit away from the summer heat. It can still be hot though, so make sure you have sun protection and carry water with you.