We found that they complemented each other well. Check out the Japan National Tourist Organization website. It has lots of great information. Bring and use sunscreen. While the weather can often be overcast in Japan, the sun is still a factor.
Japan is about the same latitude as Central California.
One of the best ways to get from Narita airport to Tokyo is the Airport Limousines . These are comfortable buses that take you from the airport directly to most major hotels. They are also one of the least expensive ways to get to the city. We were lucky in that it only rained one day of our vacation. Bring a light backpack for your daily travels.