Free shuttle bus service is available at Terminal F, Gate F-14, to Gate C-16 (Terminals C,D and B) and Gate A-1 (Terminals A-East and A-West). Buses at C-16 and A-1 provide service to Terminal F only.
http://www.phl.org/passengerinfo/pages/faqs.aspx
I'd bet against that connection working out based on the shuttle timing. You cannot walk it inside security AFAIK.
Typically the delivering carrier is supposed to make you whole (in this case AS) but I'd still deal with US as they're the ones who can more easily book you on that next flight, assuming it has seats.