Paris to Amsteram...where to stop in between?

You could stop in Bruges, Belgium. As far as the days in each place, I'd suggest 4 days in both Paris & Amsterdam.
Remember your first and last days on a long trip are essentially wasted going to and from the airport.

Helen, I would count it as nights spent and stay 4 nights in Paris, 2 in Bruges, and 3 in Amsterdam if I were stopping midway. An alternate stop might be Antwerp. In reality I would probably spend 4-5 nights in Paris and 4-5 in Amsterdam.

You will find that the counting is easier if you count nights rather than days.

Day 0 is getting from Canada to the middle of the Atlantic.

Day 1 / night 1 you land in Paris (what time, early morning?) Most of that day will be getting your bearings, getting out of the airport, getting into your flat or hotel room, being tired, being jetlagged, trying to stay walking outdoors in the fresh air as much as you can, and getting to bed (finally!!!!) at something like Paris bed time.

Day 2 you can start to sightsee...

and so on.

The last day will likely be devoted almost entirely to getting packed up from your Amsterdam houseboat/hotel/flat and getting to the airport 3 hours before departure(what time?).

Since you will be in Amsterdam in April, can we conclude that a full day there will be taken up with the tulips, crocuses, hyacinths and daffodils at Keukenhof? If not it is worthy of consideration.

Amsterdam and vicinity are easily worth 4 or 5 nights, and another when you count in Keukenhof, and another if you want to go to Kinderdijk.

Paris is easily 5 or 6 nights to just get a taster of it, enough to know you have to return.

Bruges/Brugge can easily take a full day, so 2 nights, or more, or you could consider Antwerpen or Gent, depending on your interests. You will be going right through Antwerpen on the way, Gent is just a few minutes west of Brussels, and Bruges/Brugge is about an hour or so from Brussels.

The big problem is you have too much vacation for your vacation. You need a bigger pot to put all this into.

You will need to cut or economise somewhere and realise that you need to be a bit superficial along the way. I see 12 to 14 nights which you have to squeeze into 9 days. How many nights is that, 7?

Paris and Amsterdam can easily consume 9 days of sightseeing, especially considering how many wonderful day-trip destinations are easily accessible by train or bus.

Personally, I wouldn't add a stop in between.

You are all so helpful! Thank you for taking the time to answer us travellers who write in needing advice. We will have 9 full days there. I have counted the two days of travel to and from Europe as write-offs, over and above the 9. Thank you again.

I'd select Antwerp if you really feel you must throw another country into the mix. But honestly, if this is your first time in Paris and Amsterdam, then take a train to Antwerp, spend one night there and part of the next day and then move on to Amsterdam. There really are a lot of very cool places you can day trip to from both Paris and Amsterdam if you want to experience something else. BTW, I have visited both Paris and Amsterdam multiple times and STILL have not been able to see everything I want to in either of those cities. So even if you had 9 days for each of them and you didn't venture outside either for day trips, you still won't run out of things to do.

I have received a PM with further questions. In several hours, when I return from bell ringing, I shall answer them here so that others may benefit from the knowledge.

I would not stop in another place "on the way". 9 days in total mean 8 nights mean 7 full days (in which an intercontinental air travel is not at the beginning or end).

Instead, I'd keep the option of doing some day trip out of Amsterdam, which you can decide once there.

If you just want to stretch your legs, then you can schedule your Paris-Amsterdam trip with two tickets on high speed Thalys trains, so that you depart Paris early, stop at one station, put luggage in the locker, go walk around and take a later Thalys train to Amsterdam. You need to make 2 separate bookings for that. It is a plan that might work as long you don't see it as some opportunity to race through a city trying to cover everything, but just an opportunity to walk around, have lunch and that.

Antwerpen offers the easier stop like that, the most interesting part of town is just starting to walk from the station.

Helen,

A few questions have come up -

About what there is to do and see in Antwerpen, should you decide to stop over there.
First you will need a ticket which allows the stopover. If you are using the high speed train - the Thalys - between Paris and Amsterdam you can't hop off and hop on a later one because all seats are reserved and your ticket is for only one train. You can get a ticket Paris to Antwerpen and another from Antwerpen to Amsterdam but we aware that that will likely be more expensive. If you were routed on the International Intercity slower train between either Brussels or Antwerpen, yes you can take any hourly train on the International route and you could easily stop over.

Antwerpen has a 4 level station with tracks on all levels. It is a modern rebuild (just a couple of years ago) within a beautiful art nouveau building. The station itself is well worth seeing as are the city's beautiful art nouveau quarters.

The cathedral, Onze-Lieve-Vrouwekathedraal, is a gothic masterpiece, and in a beautiful part of the city with some excellent chocolatiers nearby. Or you can have modern, or post modern, or baroque, it is fun to walk around.

Or catch it next trip because you really are short of time.

Lonely Planet has a good list at http://www.lonelyplanet.com/belgium/flanders/antwerp/sights/architecture

Once you have arrived in Amsterdam, do you know where you may stay?

There are easy bus connections right to Keukenhof and you will get a map, and there is loads of information on line on their website so you can be well prepared for your day there. You just wander the paths, take in the show, wander around, do a little people watching, have a snack, wander into some of the exhibition halls, have a hot chocolate if you are cold or wet, walk around some more, have a meal, maybe have a boat ride, and when you are done take one of the frequent buses back. No guided tour needed. You won't see it all, but who does? I've been numerous time and I never have. While you are there you can buy some bulbs which will be sent to you in SK at the right time. See http://www.keukenhof.nl/en/

Kinderdijk is a village east of Rotterdam with 19 original windmills set next to water. Beautiful and exquisite. You can take a train to Rotterdam - easy from Amsterdam - and then a bus, or - maybe you'd like the romanticism and views and atmosphere you can take a waterbus to the windmills. Their official page is at https://www.kinderdijk.com/

There is one windmill in Haarlem. A nice one, quite near the station, but just the one.

Perhaps others will have input....

Thank you so much to everyone here and especially Nigel for taking the time to respond to my questions. I have not chosen a spot to stay in Amsterdam yet, no. I have had such good luck with self-catering cottages that I thought I might try that. It looks like from what everyone has said , we will focus our time in the two spots and stop trying to fit too much in. Thanks again!