London has a small international airport that is serviced by United, Air Canada, and WestJet. You can rent a car at the airport, and a taxi ride to campus costs about $40 CAD.
If flying into the Toronto Pearson International Airport or the Detroit Metro Aiport, the Robert Q shuttle service travels between these two airports and London.
An alternative to flying into the Toronto Pearson International Airport is to travel to the Toronto City Airport. Porter Airlines provides flights to the Toronto City Airport, which is then accessible by train to London, through VIA Rail.
The recommended land border crossings from the US are: (from New York state) Buffalo (Peace Bridge - more direct) and Niagara Falls (Rainbow Bridge, more scenic - obviously) and (from Michigan) Sarnia (Blue Water Bridge). The Windsor/Detoit and Queenston/Lewiston crossings are often slow with heavy truck traffic. Border wait times can be checked here. The document requirements are the same for the land border crossings as for airports.
If you are driving to London, here are directions to the University campus:
From the 401
From the 402