Hi suman,
Your requirement will be fulfilled in shipment module or transportation management.
You have to create inbound delivery for purchase order Before doing MIGO. in that inbound delivery document you have to maintain probable delivery date and packing details. Against inbound delivery you have to create shipment document in that Route (masters to be maintained for route),agent (vendor) to be maintained . you can maintain pricing condtions for routes and packages (Truck / load) . for shipping document and pricing conditions PO will be generated automatically. entry sheet will be posted and you can pass MIRO against shipping cost document or for entry sheet.
If you want to add these cost in inventory also you can maintain customization also.
Regards
Krishnareddy.A