20 days in Sep/Oct

Hi there!

I really love your trip! Almost 3 weeks Japan with an other great destination everyday.
Also love the idea of day trips, this way you have great flexibility to switch things around and even make changes if you wish.

Looking at possibilities, I think you have 2 that would make sense.

The first is the 14-day JR Pass + normal tickets. You could fit most of your long distance (expensive) travel in the validity period, with some switching around of days/plans. For instance, you can use the JR Pass from day 4-17, by moving Dinsey land to day 3 and Nikko to day 16. This way you would have most travel covered and you could supplement the rest with some local tickets.

The 2nd option is the 21-day JR Pass. This would allow for the most flexibility, you could go where you want every day and travel as the fancy takes you. The price difference would not be much with the 14-day JR Pass. The upgrade cost is 12,800 Yen. With the 21 day JR Pass the return to and from the Airport is also covered. For instance a return Tokyo - Narita Airport with the Narita Express is around 6,000Yen leaving just 6,800Yen for you to travel to make the upgrade worth it price wise.

As last advice, your time in Tokyo is somewhat limited, so I would make a list of things to visit and decide what you wish the see the most. My personal addition if you are new to Japan would be a visit to Shibuya it is a very interesting area with lots of things to see, the worlds most busy (and famous) crossing is there too.

Make the most of your trip and let me know if I can help with anything!
-Daniel