[Nihoxdria]

Wow Tough questions! Best place to visit without tourist overload....well anywhere in the mainland is going to have an overload of tourists. so we'll have to get to that a little later. Focusing on what i know hardcore:
Fukuoka!!!!! Fuku and Shinjuku are the BEST places to shop! Flags in Shinju is right next to the station and is a 10 story facorty of shopping heaven! not to mention the food is awesome.

As far as your secret place...I'd have to tell you to stick to the shrines. Though they are tourists stops, you'll find that they're often overlooked at "boring" ^_~ What most people DON'T know is that the shrines host annual local festivals during the spring and winter that few tourists stop in on and end up missing pure Japanese culture at its best.
Also, the cherry blossom festivals attract lots of people on the mainland. But if you slip over to Tsuyama Castle you'll have the best site in the world to watch! the ruins host over 5,000 trees and going at night means you get to see the entire place alight in candlelight glow when they hang the lanterns. Sakura, it's BEAUTIFUL everything lights up and the blossoms look like glitters of soft white snow in the dark. ^^ you'd love it!