Here's where I'm at;
Packing
I just finished packing today, after a few trial runs last week. Basically, I threw in the clothes and stuff I wanted to bring and weighed the cases to see roughly how much space I had. I actually had quite a few kg left in each case which was a great surprise, so I gathered more clothes to put in. Earlier today I packed the cases again and the weight is perfect, happy days! Packing four days in advance basically means I can sleep easily for my last few days in Ireland, and spend it hanging out with family and friends instead of panicking and stressing about it the day before.
Flight details
We're flying Dublin - London, then London - Tokyo with British Airways. They have one free 23kg check in bag, carry on hand luggage and then also a handbag or briefcase. I think 23kg check in is a tiny allowance for moving around the world for a year, but thankfully they only charge €75 for another 23kg bag, so I've got 46kg total, plus a carry on bag and a handbag.
As an interesting side, you can check out what the onboard movies, tv shows etc will be on your flight on your airlines website before you travel (I think most airlines do this). For BA, it's here: http://www.britishairways.com/en-gb/information/entertainment/in-flight-entertainment
Hamamatsu, Shizuoka
Excited to announce this is the exact place I'm going! It's a city of about 800k people, situated on the bullet train line and halfway between Tokyo and Kyoto, about 1hr 30mins from each. The bullet train is expensive, and I can get a bus to Tokyo for much less but it takes like 4-5 hours. Overall, Hamamatsu seems to be a good location for travelling easily around Japan.
Tying up loose ends
There are things to do before leaving your home for any length of time. I decided to get my laptop fixed - it's been overheating and I felt it was easier to get it sorted before I go. I threw out a lot of clothes I hadn't worn in the past year or so (well, gave them to charity shops). I cleaned my room! I'm meeting up with some old friends this week. I guess it just depends on the person what needs to be done.