I'm considering a quick hop to Tokyo and wanted to take advantage of my Free Weekend Nights. Unfortunately I'm told they're only good at category 1-4 hotels and it appears that the 2 Tokyo options (Westin and Sheraton) are out of reach at Cat 5. The only other option I see at spg.com is the Sheraton Yokohama, which they say is 18 miles away from Tokyo.

Are there any other *Wood hotels I should look into? Any chance that SPG would allow me to convert my four Cat1-4 nights into say two Cat 5 nights?

Is the Sheraton Yokohama Bay and Towers simply too far from Tokyo to make a 3 day trip worthwhile -- or are there fast commuter trains that can get me into Tokyo in a reasonable time (30-45 min) that might make it worthwhile to stay out there for free?

Any advice is greatly appreciated!