Can anyone please give me a first hand account on Marine Security Guard Duty?

I'm currently serving in Japan and I'm nearing my one year mark on island. I have become disillusioned here with the fleet life and I don't like my job. I've lost all the motivation that I've had since joining the Marine Corps. All I want is to be happy with my job and be treated like an adult. I've become very interested in doing MSG duty for various reasons. I could see 3 different countries and actually get to enjoy it(unlike the rules here in japan), I feel like it's different then the actual typical fleet life, and I feel like I'll be treated like an adult, since I'll be working directly for the DOS. I have a few concerns and those include, being in a situation worse than here in okinawa and being fooled by the grass not being greener on the other side(which has fooled me many times in my career so far). I would like to get first hand information on the application process, the actual school, and how life in MSG actually is once stationed. I appreciate the help ladies and gentlemen