I would be a little cautious about assuming the Park Hyatt is
that convenient for Narita. Assuming you want to plan on arriving at the airport 90 minutes before your flight at 10.45am, either:
- you'll be catching the 7.05am Limousine Bus to arrive at Narita Terminal 1 at 8.55am; or
- you'll be catching a taxi to Shinjuku station in time to get the 7.06am N'EX which arrives at Narita Terminal 1 at 8.36am (so be stepping into a cab about 6.50am I would suggest).
Alternatively, you could stay at the Four Seasons at Marunouchi which is 3 minutes walk from Tokyo station, and catch the 8.00am N'EX getting to Narita Terminal 1 at 9.01am.
Realistically speaking, you're 45 minutes closer to Narita by staying at the Four Seasons, which is also truly a world-class hotel.