on searching for the shortest route, here is the link for that from Manali to Hardwar which is given as 354 kms (with slight variations may be there)
www.mapxl.com/path-finder/ map_routing.phtml?config=routing
Trust you will find the site useful. About the rates etc, check with hptdc people or gmvnl for your travel. you can even try their hotels which are very good and simple with good food.