Try this,
>>> raw_location = {'Raynham, MA Topsham, ME', 'Irvine, CA Bradenton, FL', 'Savannah, GA Cary, NC'}
Output:
>>> {", ".join(["/".join(w.strip().split(" ")) for w in word.split(",")]) for word in [s for s in raw_location]}
{'Irvine, CA/Bradenton, FL', 'Savannah, GA/Cary, NC', 'Raynham, MA/Topsham, ME'}
#For set of list
>>> [{", ".join(["/".join(w.strip().split(" ")) for w in word.split(",")])} for word in [s for s in raw_location]]
[{'Raynham, MA/Topsham, ME'}, {'Irvine, CA/Bradenton, FL'}, {'Savannah, GA/Cary, NC'}]
Edit 1:(From comments by OP)
>>> obj = ({'name': 'Alex Finkelstein/Nathan Mao', 'index': '1', 'location': 'Raynham, MA Topsham, ME'}, {'name': 'George Alexander/Ryan Xiao', 'index': '3', 'location': 'Savannah, GA Cary, NC'}, {'name': 'Bryson Cook/Graham Hadesman', 'index': '4', 'location': 'Sewickley, PA Bradenton, FL'})
Output:
>>> for d in obj:
d['location'] = ",".join(word.strip().replace(' ', '/') for word in d['location'].split(','))
>>> obj
({'name': 'Alex Finkelstein/Nathan Mao', 'index': '1', 'location': 'Raynham,MA/Topsham,ME'}, {'name': 'George Alexander/Ryan Xiao', 'index': '3', 'location': 'Savannah,GA/Cary,NC'}, {'name': 'Bryson Cook/Graham Hadesman', 'index': '4', 'location': 'Sewickley,PA/Bradenton,FL'})