Rescue Advice

Okay, I was asked to pick up and deliver a 6 mo old Sammy puppy from some family with 9 kids and hold onto it until the 12th when we will either meet the new owner in Omaha or someone will meet us in Mpls to take it to the new owner. Its a rescue situation. Current owner is threatening to put puppy down if it doesn't leave and leave soon.
This puppy has been kept outside all this time. I know to check for fleas. Would it be wise to worm it too? Unfortunately, I have to get it after work so I won't be able to have a vet check it out before bringing it home.
What is the best way to do this? Back when I've fostered before, I've never had problems but its been years.... Help!