Itinerary 2 weeks (Tokyo-Fukuoka)

Hi- I have booked flights for late March/early April. We fly into Tokyo and out of Fukuoka. Trying to figure out how many days for each place. I feel overwhelmed! Also need help to decide where it's better to stay longer and do day trips and where it makes sense to move on and spend the night en route to next stop. So far I think we'll spend 5 nights in Tokyo (probably doing one day trip during that time.) Then head to Kyoto. Don't know if we will/should stop along the way or just go straight to Kyoto and use as a base. Maybe 4 or 5 days in Kyoto? (Again, if we use as base we'd stay longer but maybe makes sense to leave and spend a day or 2 somewhere else before heading to Kyushu). Part of this is also ease of train access. Then Kyushu, probably have about a week to explore. We need to end up back in Fukuoka for flight home. We are very interested in seeing the natural beauty and getting away from cities. Also went to splurge and stay a few nights at an amazing ryokan with onsen. Is Kyushu the best place to do this? Any suggestions for specific ryokan? Not willing to spend a crazy amount ( I saw one for $1500usd per night!) but will splurge for a night or 2, maybe up to $700ish a night.
Sorry for long post- so much to see and do! Open to all suggestions- we could spend more time on Honshu as well. Thank you for any advice!!