Ok - this will cover Paris proper. We rented a lovely apt in the Notre Dame area. Once the hired car had dropped us off, we decided to wander around and get our bearings. First on our list was finding a grocery named "Naturalia" as my wife is Gluten-Free, and it was one of the places our pre-trip research had identified. Nearest one was about 10 minutes away by foot, so we went for a stroll. Not a large selection, but enough to add to the iron rations that we carry around. We later found that Monoprix (Target style store, just south of Notre Dame) also had GF food, and at better prices.
Notre Dame area - lots of stuff. I'm going to concentrate more on what we found around there that was useful for the traveler. There are multiple metro stops all around the area. We found that St Michael was the most useful for us. That was both Metro and RER. From that stop we went to Les Invalides/Rodin, the Musee de Orsay, and out to Versailles. We walked to the Louvre along Rue de Rivoli (10 minutes) intending to use the Carosel mall entrance, but discovered that we could get in just as easily via the Pyramid (YMMV, depending on how busy - we did use the Carosel Mall to leave). At the Hotel De Ville (government offices just north of Notre Dame) there is a post office. We went there on the last day to mail out some postcards. Should have gone there much earlier, as the french PO also sells cell phones, etc. Would have been a lot handier then scrounging for WiFi, cause we could have gotten a french SIM card with voice and data plans, rather than roaming on our Ireland (from earlier in the trip) one.
Louvre. Lots of fun, highly crowded. Lots of pictures. Had one of the most expensive hamburgers I have ever bought (25 euros) in the cafe downstairs, but we were starving.
Rodin museum. We arrived just after some group was having a protest across the street. There were about a bazillion riot cops on the street outside. Later discovered it was a protest about Pharmacists not wanting Monoprix and similar stores to be able to sell medications. On that note, there is a Pharmacy just north of the Hotel de Ville government bldg that is open 7 days a week. Google for Pharmacy of the Archives if you need to find something medical. They tend to cluster, look for the green cross neon signs.
Les Invalides/Army Museum. Big. Army museum has a wonderful collection of medieval armor, similar to the Tower of London. Just across the street from the Rodin, short 5 minute walk. We used the Les Invalides metro station for both.
Versailles. RER from St Michael. About 10 minute walk from the station once you get there. Avoid the trinket sellers. Full tour will take several hours, includes a lot of stairs. If you have mobility issues, ask for the lifts. The train tour outside is nice, but goes over cobbles, and is extremely bumpy.
Musee de Orsay. Can't remember if this was Metro or RER, but was from St Michaels. Its only a couple of stops from St. Michaels. We did this on the way to the Effiel Tower and the Arc de Triophe. Went on "free" day, which turned it into one of the most crowded places we had been all week.
Musee Nationale de Moyen age (Medieval). This is in the latin quarter just south of Notre Dame. 15 minutes walk. Just down by the Sorbonne and across the street from the Monoprix we found. We really enjoyed it, but we have a personal interest in the time period. Lots of tapetries, including the Lady and the Unicorn series.
Tower and Arc. Went to see them at sunset, when they turn up the lights. Magical.
Montmatre. Was a rainy day, so we didn't do much wandering. Saw the Dali museum, as well as Sacre Coure. Good prices on the touristy gee-gaws, as compared to other locales we had seen.
k. Thats everything I can remember. Will add more detail if I can think of it.