Sanghar city is about 4-5 hours drive from Karachi. Road condition is ok. Its not bad so any car can go there.
Do you have any lands there ? Its not a picnic point but we can enjoy anywhere since its our country
Better to go there in sunlight(early morning) and when returning reach Hyderabad before sunset.
It is nothing like Mangla Dam or Tarbela Dam. It is a very small dam. Chutiyari reservoir is supposedly a nice place to be. There is also JAMRAO HEAD few hours away which was a beautiful place some 15 years ago
Anyway from Sanghar City Chutiyari Reservoir is approximately about 1 hour drive.
In this heat if you are going to visit only Chutiyari Reservoir and then return to Karachi same day it is not worthwhile.
Winter is the best time to travel in Sindh.