Thanks for remembering me. I only check this site when I can't get anything done and this is more fun than Bubble Town or Solitaire.
Unfortunately, decorating/glazing/cutting designs in the pottery is not a full time job in the samll "art" studios, and in making the pottery, that step is often done only a short time in a long process. You have to be a little lucky to see that step as you visit the smaller kilns. Sometimes the potter will be throwing the clay while some other workers will be decorating, but in the smallest, it's a 1-man show.
In Arita, you might check out the "Arita Porcelain Lab."
http://www.aritaware.com/global/factory/With its large scale, there might be few workers there putting down glaze. You can also contact them via their page and see if a viewing of the floor can be arranged. Most potteries that I've visited, you have to be friends with a potter because the work space is small and clay covered. Some places have windows that you can look into the workspace, but in most it's out of sight. This place is large enough that you might get a good view. This one as most potteries in Arita are located near KamiArita Station, one stop beyond Arita (to the East). The main information center that can help you out is in the main station of Arita, though. I would stop there first and see what the info center can arrange for you.
http://goo.gl/ao7CrsAs for Okawachiyama, it's only a 25 minute train ride to Imari from Arita and to save time, you can take a 10-minute taxi to Okawachiyama (I think it was Y900). It isn't that far and with 3 people it isn't too expensive. The buses are a pain as they're so few (about 2 hours between rides) but they're only Y100 from the station to the town.
I looked for people working there just last July, but even though I got to talk with some potters, it didn't seem as if any were working that day. However, there are so many small kilns in a tight area in that town that you may stumble across something and be luckier than I. My guess though is that anybody working was in their studio which wasn't public.
I can't really recommend any restaurants. I go for cheap common food that's decent, and that's easy for me to find. The last place I ate in Arita was a noodle shop by the station.
https://www.flickr.com/photos/anaguma/14669995980/In Imari, I ate at a Gusto next to the station because it was a very hot day and they had a drink bar (all you can drink-- coffee to melon soda).
Sorry I have nothing definite.
