So... I just finished my "Speedrun" of Japan: All major cities in the major regions covered in 10 days. Initial thoughts:

1. If you plan to do it this way, the 7-day Japan Rail Pass is absolutely necessary, and pays back for itself multiple times. The other passes not so much: I found getting myself a normal IC card (Icoca this time around coz I already have Suica) for normal intra-city travel is much more convenient and you don't really lose much vs city travel passes.

2. The rail timings will be tight. Like *real* tight, especially from Nagoya --> Sendai --> Sapporo, primarily because Hakkaido does not have a Sinkan system *yet* and relies on slower express trains. You also have to wake up in the wee hours of the morning more than a few times.

3. 10 days is enough (barely) if you know what to cover (this is already my 3rd time going to Japan, mostly Tokyo, so less to cover). For first timers however, 14 days is reccomended so that you can cover more stuff around Tokyo on the second week. You'll move around *a lot* though (maybe even up to the last city train) expect to rest only while travelling between cities, and when you're sleeping.

4. Japanese language skills, while *not* absolutely necessary, can be *very* helpful, especially when going to the less touristy parts of Japan. It also helps open doors to very interesting conversations.

5. The GAC LTE MIFI is totally worth it. It's fast and lasts for at least 3/4 of a full day. Coverage wise, the only trouble I've had was in tunnels (duh... but the Sanyo Shinkansen has a *lot* of tunnels... really) and in the more *ulu* parts of Hokkaido. Otherwise it works pretty perfect.

For a detailed breakdown, maybe later. For now, all I could say that it was a hectic 10 days, but great fun nonetheless.