I think that the inability to rate songs on the GoFlex Satellite over wifi could be a matter of the device being read-only in that operational mode (and ratings are usually written back to the song file itself). Windows Surface Pro adds the option of accessing the device via USB where writing should be no problem, though that can be a bit of a cable mess (unless there is some way to do that wirelessly?).
I had been thinking of using iTunes for Windows just because I'm already familiar with iTunes, but apparently it has not been updated for Windows 8 to be touch-friendly, so it does not seem like a good while-driving solution. You mentioned Windows Media Player, maybe that's the way to go then. Really, any song player that has large text (for song/album/artist/playlist displays) and big buttons (for track pause/skip and for rating up or down) would work for me. Is WMP specifically good for this? Any other suggestions?
This also affects my choice of how to rip. I want lossless audio, but Apple has their own format... I'd like the files I rip to the GoFlex to be playable on the Windows Surface Pro but also from my Macbook, and I don't know which (if any) lossless audio formats are readable by both. And again, I want my song ratings to be visible from either platform. Any advice here? (And I am still concerned about your comment about having lost your ratings in Windows... Anyone have any ideas about why this happens and how to avoid it...?
I realize I'm getting pretty far from what people on an iPad forum are likely to know much about! Is there a comparably helpful forum for Windows tablets that anyone could point me to?
Well, I picked up an Acer W3, and it was defective out of the box.
I've also discovered another potential problem with trying to use an iPad for everything... It seems like if I set it so that its wifi finds my GoFlex Satellite, the GPS program no longer gets traffic data, because it is trying to get it from the wifi connection (whereas when there is no wifi connection at all, it gets it from cell). It's one little gotcha after another, it seems...
edit: I think I found a fix for that last issue.