Suggestions/thoughts about my itinerary?

I’ve been to Japan twice already and I am going again for an 8 hour layover soon at Haneda, I have some ideas but I wanna know what you guys think

I plan to go to Shinagawa or more preferably Hamamatsucho to go around and shop and eat a bit, I wanna go by subway or monorail

After that, I’m thinking going to shinjuku and back would be too far and just not worth it, so my other thought is to go from the first place to the Haneda Garden people always talk about and spend the rest of my time there since apparently it’s huge

Thoughts? I think this is pretty solid