Don't pump the tires up more than they are rated for, it makes the bike ride pretty badly and can make it unpredictable in the corners
Make sure the bearings have good grease and oil the chain regularly with something like chainsaw bar oil. That seems to work the best for me, it holds up and doesn't sling off the chain like used motor oil does.
I never have tried pulse and gliding on my bike. It is tall and since I sit straight up on it I slow down really fast. I bet if you could get the aero even slightly improved on your bike it would probably make a huge difference in coast times. Maybe try a small windshield that is as wide as your shoulders. That could help direct the air a bit better than just hitting you straight on.
If you don't know the mileage you are getting now, riding it as it is for now would be a good thing to do to get a baseline mileage number so you know what changes actually help.