Great Western Coffee Shop

Planning Interrail trips and looking for hops to the continent - I know that a number of crossings are road-vehicle-only.  I have this list for foot passenger routes. What should I add that does not involve flying?

Newcastle   Amsterdam
Hull   Rotterdam
Harwich   Hook of Holland
Dover   Calais
St Pancras   Lille, Brussels and Paris
Newhaven   Dieppe
Portsmouth. Le Havre
Portsmouth   Caen
Portsmouth   Cherbourg
Portsmouth   St Malo
Portsmouth   Bilbao
Portsmouth   Santander
Poole   Cherbourg
Plymouth   Roscoff
Plymouth   Santander

ah - and what about.
Flixbus ... and other operators. Eurolines / gone?

Add St Pancras to Amsterdam Central, but it will be suspended for a while after June for the reconstruction of Amsterdam Central

This has been updated that after June the service will now run direct London to Amsterdam but Amsterdam to London you will need to change at Brussels to go through passport control.

https://www.seat61.com/trains-and-routes/london-to-amsterdam-by-eurostar.htm

Many thanks for the Eurostar / Amsterdam update.

Corollary - which of these routes (i.e. post pairs) are friendly to use for local train - ferry - local train transfer?   

Reading about it, for example, I see that Newhaven - Dieppe has a 250 yard walk at Newhaven, but a walk of 10 times that distance at Dieppe.   Portsmouth terminal is not exactly close to Habour, or Southsea, or Fratton, or Hilsea stations.  And so on.  Do any remain easy?

Harwich–Hook of Holland is easy. At Harwich, the station and ferry terminal are the same building. At Hook of Holland, you walk down the ramp (which admittedly is very long) into the terminal building; the metro station is just over the road.

Poole is annoying. It's got a railway right up to the ferry terminal and plenty of terminating trains that could be sent along the branch, but no Poole International station.

Also   Poole -> St Malo

I was really disappointed that I could not find and Ashford / Folkestone to Calais / Bologne bus link or way for people without vehicles to make the short crossing at one point. Good that P&O have resumed accepting foot passengers on 3 services a day.  Asking for Ashford to places on the continent, Google suggested I change trains at St Pancras!

I have used Harwich / Hook, but not since the train service at Hoek became a metro. The overnight crossing is a good (if not cheap with a bed) starter - from Melksham mid afternoon - sleep on the ship, and then off to Utrect or Venlo and onwards to Frankfurt, Nurnberg, Aalborg or Thun - all of which I have done.

Portsmouth to Caen is actually (pedantry alert) Portsmouth to Ouistreham, a few miles north of Caen.
Many years back I had a few days in Ouistreham going as a foot passenger from Portsmouth (I recall we took a coach from Bristol) which was very enjoyable as well as historically interesting with it's D-Day connections....and the beaches are impressive.
I don't recall that the transfer from coach to boat was too taxing although I was in my twenties then.

If the service at Hoek is a metro, presumably Interrail tickets wouldn't be accepted on it?

We are aiming to do our first interrail trip this spring, so it would be useful to know, in case we decide to head out or back that way.