Speaking from experience as someone who has done all these things and is happily married now with over fifteen years in Japan, just...slow down. You're putting the cart way, way before the horse.
If you haven't spent considerable time here yet, you have no idea whether you'd like living in Japan for a couple of weeks, let alone the rest of your life. When I first came here, I was very excited about/interested in the prospect of living here, but the decision to stay long-term was something I only made after spending literal years here, when I realized that I was genuinely content with my life and could realistically commit to a life here. It's in no way something you should be thinking about or prioritizing if you haven't even gotten here yet.
You also say nothing about what your level of Japanese is, what your skills are or what career you intend to have, etc. etc. All these things are very, very important in building a fulfilling, meaningful life for yourself in Japan. If you're just expecting that being here, doing anything, and being married to a Japanese woman are going to make you happy, then you seriously, seriously need to reconsider your priorities.
Not trying to be discouraging, just realistic. If you think you might like to try living here, then take it one step at a time to make that happen.