I'd probably take the JR Narita Express train to Shibuya and a taxi from there.

If saving pennies, I'd take a Keisei Skyliner train to Ueno and walk to the Hibiya Line, which goes to Roppongi. But if you don't fancy hauling bags through the subway, the first option is more comfortable.

Taxi from TCAT is possible. It's a 20+ minute ride, I guess....