Originally Posted by
evergrn
You'll get to Tokyo by 6pm, probably before. If it were me, I'd at least get a cheap hotel room, maybe in Ueno. Hang out for 6-7 hours. Start out with maybe a trip to Sky Tree to catch the view of Tokyo at dusk and take in shopping/dining down below. Follow it up with a visit to Roppongi or Shibuya for nightlife. Return to Ueno, maybe have late night ramen, then crash for 4-5 hours. Forget about the tuna show.
If you're not going to get a hotel, then I agree that the onsen option seems your best bet.
After reading it all, I think your plan is best but still trying to evaluate what to do from noon to morning if no hotel. Onsen wise do I need to wear beachwear, I read I have to be nude, but they said valuables stay on the shelf, so no go as I would have my passport and all, I will check if any have lockers although still, is it secure? Also, public transport should cover it all, should I get a card for a day or two or what is the best way. Thank you so much guys!