ChaChaanTeng,
You do understand that class size of pre admitted students is less than 80? It is harder to get directly into Ross than Northwestern.
Northwestern is an excellent school, having both option is a very nice problem to have but under no circumstance is Ross choice second best.
You will need Kellogg MBA to compete with Ross undergraduates. As for “network”, particularly in NYC, you cannot do better than Ross, maybe Wharton.