Ok- will be saving Italy for another trip sometime down the line if I can go in the future.

July 14-19: Paris (arrive 7AM), train by Eurostar to London $70, 7AM-8:30AM on the 19th
July 19-25: London, train by Eurostar to Paris $100, 5PM-8PM on the 25th
July 25-29: Paris, stay at airbnb’s within Paris 25-27th until the night before, then train to CDG airport late on 28th and stay at airbnb near airport. Depart 10AM for U.S. on the 29th

I could also arrive to London earlier (maybe within a few days of landing) and then spend a week there before spending time in Paris.

Don't get this need to stay near the airport. Roissybus starts operation at 5:15 am and takes an hour. RER B takes about half as long and starts at about the same time.

Again, please be careful with AirBnB and only book a place with a registration number.

Personally, I would put all the London time at the beginning. You have plenty of time to get into Paris for a midday Eurostar.

Just an FYI....we just returned from Paris this past Thursday. We had been in an apartment, but decided to stay in a hotel near the airport on our last night so we wouldn't be stressed out the day of travel. Stayed at Oceania, $169N, which may be out of your budget, but it has a pool, very modern and clean and a free shuttle to CDG. Since you have an early flight, it's an option. CDG is big, with two terminals, so leave yourselves lots of time.

BUT...the best part is that it is on the edge of a small village (popultion 884 per Wikipedia) called Les Menlis-Amalot. We walked down the streets of this tiny French village, quiet as can be, enjoying the charm. Had an excellent dinner, formule for 16E practically next door to the hotel, in a delightful restaurant, L'Pomme d'Or.

That sounds like a very nice place, but it's at least 3X what we normally pay for accommodations anywhere in Europe, including at airports. Might work for a lot of people, though.

StCirq,
Yes, it was a bit pricey, but it was a last minute decision, and given the amount of money we had already spent during our two weeks, we were ok with it.

there's a different value from a tourist's point of view on a trip of a lifetime than someone living in Europe and traveling lots and lots. One-time splurge can be great.

I agree Palenq. I've never been to Europe before, and I don't see myself going every year so I think the splurge will be worth it. I'll still be staying in the cheapest airbnb's but the trip in general is the splurge.

Final itinerary, just purchased Eurostar tickets:
July 14-18: Paris (arrive 7AM), train by Eurostar to London $70, 6:15PM-7:40PM on the 18th
July 19-24: London, train by Eurostar to Paris $70, 8PM-11PM on the 24th
July 25-29: Paris, stay at airbnb’s within Paris 25-27th until the night before, then train to CDG airport late on 28th and stay at airbnb near airport. Depart 10AM for U.S. on the 29th

The reason why I'm looking to stay at an airbnb on the last night before flying back home is because the flight departs 10AM, and because it's an international fight, I'll have to be there 3 hrs early which is 7AM. I'd rather not be staying in Paris, starting the day 45 min away already and calm my nerves by starting much closer to the airport as Calabria62 had mentioned. I'm not much of an early person so also so I'm ok with saving an hour by staying close to the airport on the last night.

cjaay - looks like a fantastic trip and you have planned it very well I think. I well understand wanting to stay at the airport before In early departure - I have the same in reverse when I fly to Madrid en route to Valencia next year; the flight gets in at about 8pm and though I could get the bus into Madrid and spend the night there before getting the train to Valencia, I thought it would be a lot easier at that time of night just to hunker down in an airport hotel, have a nice meal [hopefully] and then get the bus in the morning. I will be spending 3 nights in Madrid at the end of the trip anyway so I don't think that I will feel deprived.

With the strike situation affecting RER transport to in Paris potentially makes it all the better to stay near the airport - how will you get to airport from yourn airport area airbnb?

Exactly, PalenQ. That's why I would feel way more secure getting the last night near the airport also.

We unfortunately came into Paris by train a few years ago -- just in time for the rail strike. Arrived at the wrong train station and couldn't figure out what was going on. Thankfully I speak enough Spanish and can read French fairly well, so on the schedule board I was able to read that there was a strike.
The Metro workers were sympathy striking and we had an awful time getting around Paris. What a PIA. We tried to make the best of it, but missed Giverny, Versailles, and wasted lots of time, so it definitely put a damper on our vacation.

We solved the train/Metro problem getting to CDG by taking the airport bus which thankfully had a pickup close to our hotel. The bus is my favorite way to get into Paris. No fussing with luggage on the Metro, getting it up and down stairs with no working escalator... Just put your luggage under the bus and relax in a comfortable seat to the airport.

You've done a good job with your itinerary cjaay. I hope you have a lovely vacation!

Good itin, now what are you going to do in each city? I really advise you get out of Paris to see a little of real France. Maybe take the train to Epernay to see a small town that also happens to be one of the two Champagne centres?

Getting out of such a big city as London is a lot harder (there is so much to do) but maybe Brighton or Oxford

ditto to Bilbo's suggestion of doing easy day trips from large tourist cities to smaller tourist cities - I'd suggest Reims however for Champagne tours and a historic city with great cathedral. Epernay is for Champagne purists as I believe it is a bit more prestigious for its bubbly than Reims but little else to see except roam around a typical French regional town - far less touristy than Reims. Chartres is one of my favorite day trips -thriving regional city plus of course world-famous Mother of all Gothic cathedrals.