Can you still drop the tour? It's easy to get to and explore the
Asakusa Kannon Temple by yourself, and the market street leading up
to
it is very interesting - you might want more time in that area, which
also includes many traditional Japanese craft shops. The Imperial
Palace and most of the park surrounding it are closed to visitors
except for two days a year, and the closest you can get the rest of
the
time is a distant glimpse of the Palace from one corner of that park,
so I wouldn't really call it a must-see experience for someone on as
short a schedule as you are.

I booked my entire trip as part of a tour package... but I think I can
probably just go independent, right? They can't chain me to part of
the group, right? =) When the Palace is open those two days... what
exactly do the visitors have access too? Actually, when I am in Kyoto,
I think the Imperial Palace will be open for the two days I am there!
Although... no one lives there, right? Not sure about Tokyo's Imperial
Palace's opening days...
Thank you for the tips on Shinjuku, Harujuku, and Daikanyama too!