Eurostar

Pros

• I did the first leg of your trip. Eurostar from Amsterdam to Belgium, and then to London. It added a lot of time, and expense vs taking a Ryan Air flight, but it was very pleasant, and I love trains.
• Finish with Eurostar back to London. Its direct high speed trains take around 4h45, with several departures each day. I just prefer this one because it starts gently, puts the awkward jump in the middle, and gives you an uncomplicated...
• Take the Eurostar from London to Amsterdam. It’s comfortable, takes you city centre to city centre, and saves the hassle of airports.
• the train drops you right in the center of things at amsterdam centraal, which seems like a total no brainer if you want a relaxed journey.
• Day 6 Eurostar to Paris

Cons

• You'll also be exhausted from the Paris trip, if you're doing it, do tickets on the Eurostar where you get fed (middle tier upwards) - don't bother with dinner in Paris.
• Because it's so fucking expensive.
• You can't just walk on Eurostar like you do with regular domestic train, it's almost as annoying as an airport but now it's almost 5 hours on a train Vs 30 min flight. I think for a trip to Paris Eurostar usually wins preferable but Am...
• The train works as a faster alternative when doing London to Paris or Brussels, but that’s pretty much it.
• I personally prefer the train to Amsterdam but it is longer and can be costly if ticket not bought in advance but overall I prefer the relaxed vibe of the eurostar as a whole compared to crazy busy airports.