Its better to plan your halt at Keylong or Jispa,instead of Sarchu;solely for the distance.We visited Leh last september and was stuck badly by landslide just before Keylong,but couldn't cross it for over 6 hours.We crossed after a bit of clearance on foot just before dark,but our car could not cross before 4 am the next day.So plan for short breaks.
Its cheaper to book the land package in Leh,or it will become very costly (unless you are a biker).If you are travelling as a family,package would be better I think.
Depending on the month you are going,there are some tented camps at Jispa just beside the river.It would be the best,but it may get very chilly at nights.