Our trip to Kyushu begins in 61 days.
The trip is 21 days long (including flights), and we will have 18 full, usable days on the ground. We've been to Japan before several times, always traveling independently. We have found that to be easy and fits our preferred style. This will be our first time visiting Kyushu, the large southern island. It's a lot of ground to cover in 18 days but I think we have a solid plan (we will be renting a car, no Shinkansen bullet-trains for us this time).
I've been deep in planning, heads-down for days in the details. I've just finished plotting about 100 POI ("points of interest") that we would like to get to, but realistically we will need to pick and choose which items to prioritize each day (this is how I plan our trips where there is no guidebook - I make my own, based on extensive research - each day we have a "menu" of sights to see, places to go, things to do, and we make game-day choices about how to spend the day).
Here's the draft map with our (currently ~ 90) POI menu items. Each numbered dot refers to a single POI item that me or my spouse wanted to include on the menu. Each item is listed in our homemade "guide book" with a rating (I use Rick's standard ▲, ▲▲, or ▲▲▲ system), a brief description of the POI, a map locator (A3, G7, etc.) and a "PlusCode" (shorthand for lat/long location, these can be used in Google Maps for precise location and driving directions). Here's an example page: POIs page 2 of 3
It's a bit of work, but I enjoy it, it typically is well worth it, and we both enjoy having all our trip details in one, easy-to-use location.
So with 60 days to go, next planning tasks are renting the car, setting up the toll road "express pass", then listing the restaurants my wife has been collecting (I'll add a page for those similar to the Points of Interest pages). Yesterday she told me: "I need to warn you: We are going to be eating a lot of sushi and super-premium beef on this trip..." Sounds good to me (Japan has many varieties of hyper-local, super-premium beef; and of course, great sushi). Yum.
In reply to the question above about ATMs, credit cards, etc. Like traveling in Europe, have at least a little cash handy for small purchases at mom & pop establishments, but do NOT carry around lots of cash; credit cards are widely accepted. Use your ATM card from home to pull the (limited) cash you'll need. Not all ATMs will work with your foreign ATM card, but plenty do (an odd one to try: many Japanese post offices have ATMs and IME they tend to accept US ATM cards, so don't overlook a local post office as a potential place to get cash).
Travel in Japan is easy and fun (more so than you might expect). Don't let fear of the unknown or worries about it being so "alien" keep you away. If you can manage in France or Italy, Japan really should be no more challenging.