I am looking at a flight for a friend from IAD to MRS, however the cheapest itinerary arrives in LHR and departs about 4 hours later from LGW. The return has a 3 hour connection.

What is the connection time needed and the process. This is for a friend who will be living in MRS for four months - she's 20 and will be lugging all her stuff with her (at least 2 suitcases + carry-on I would assume) - would this be a tough connection?

Would BA provide transportation or would she be on her own for that? Would they be able to check her & her luggage all the way through, or will she have to go through customs in LHR and then re-check-in at LGW?

Both of these connections would take place on a Saturday afternoons.

Thanks!