You need to put flyers through all the doors locally and shops, go door knocking, go back to the area when its dark and call for her.
She will need food so will be on the scavange and roads in country areas are very dangerous to cats as traffic tends to travel very fast at night.
Where was she lost? Do you live close?
You also need to get her on the loast and found registers with a picyure.
Does she have a chip and/or a collar?
I hope you find her............assune she is Tilly?