Manali to Leh is a total distance of 473 kilometers. It is necessary that you take a few breaks. Sarchu is 230 kilometers from Manali and would be a motorable distance within a day. However, the road after that can get a bit tasking. Driving continuously in this terrain is a great experience but you will need to save the energy for later. While a break at Sarchu is mandatory, it will also help if you can add a few more stop over.