you don't need a bus for Udaipur Darshan bus, all the places are nearby and you can take a walk from jagdeesh temple to city palace . the auto will hardly cost you 30-40 bucks but make sure you take an Ola or uber. you can check my blog if you want.
Jaipur and Udaipur are places that can be covered without travel agents, every tourist spot is nearby in Udaipur and for Jaipur you can directly hire a cab or rent self drive car which would be cheaper than agents. Routes are easy and can be spot on Google maps.
Greetings from Udaipur, I would recommend don't go for darshan bus, If you have licence than hire a vehicle and roam on your own, all tourist places are near by, avoid ola uber in old city area as roads are narrow so you will find traffic problems. and for any other help message me.