Overnight trip in Oze - best route and campground?

Hey yo. Some of my non-Gunma Japanese friends and I are doing an overnight in Oze. There seems to be a lot of hiking routes recommended and I can't choose which is best. We're going to be driving and parking it, hauling our gear through the marshes in typical Davey Crocket style - any recommendations on where to start and end a 2 day trip? Also, which mountain is better - Shibutsu-san or Hiuchi-ga-take? We're pretty serious hikers so have no mercy. Please help me Northern Gunma kids!

Obrigato from Ota