1. Read the section about reservations on this site first!
2. You have done the critical Eurostar.
3. You must reserve all TGV trains. The one from Paris to Switzerland is very expensive! Unless money no object take a TGV to Strasbourg and change there. SNCB site can reserve these.
4. All Italian high speed trains have compulsory reservations including ones originating in Switzerland. ÖBB  can do these. When reserving seats you book two and you’ll be sat together
5. For sleepers you book a double and you’ll be in the same room. The upper sleeper is very high up and if you have reduced mobility go on a day train. I don’t recommend sleepers unless there is no other option.
6. DB can book most of the other trains. If you change your mind you won’t get refunds on most reservations. For the dates you chose you’ll be able to reserve seats at the booking offices a couple of days before.
7. Dont have sleepless nights. It is very unusual not to be able to get your intended unless it’s a sleeper or Eurostar.
8. If the worst happens you have a credit card and speak English! Experts on this site can help.

At the time you are travelling it is highly unlikely that any of the trains you are planning will be fully booked and many of them have alternatives (Plan B options).

I assume your visit to Pisa is to see the tower since your planned train travels through Florence. There are many trains back to Florence not requiring reservation so take as long as you want and just add the next available train to your pass. It is a fair walk to the tower and back through the city centre.

As above, Italian trains are easily pre booked via OBB, as can the Venice to Salzburg journey. 

Like the previous post I would advise against the night sleeper - simply stay in Budapest an extra night and enjoy a daytime train ride to Prague. You will still have enough time to get a taste of Prague. The extra night in comfort, and daytime train will give you time to rest mid trip - you will need it. Night trains can be difficult to get a truly good sleep and arrival mid morning with luggage can be exhausting to start your exploration. There are 2 early options from Budapest that get you in for mid afternoon so still able to experience Prague at night.

Just add #9 to #7: try to be a little bit flexible and this will help immensely to curb panicky situations. On all sectors are many more trains as those you mention, though I admire the work done for this. Luz->Fir. is with changes, so is P->Luz. Practical: IF you stay in HTL and do the brekkie there:often this only starts @ 7.00-so that means hurry up to reach those trains. But all larger stations have generally also food-options aplenty (and not cheap). An early arr in a next city also means you cannot yet check-in at the next HTL.

Agree with above #5 and yorkie: unless you want it ´for the experience´ I think these suddenly revived nite trains are grossly overhyped in what they promise to deliver-plus at that time of yr days are quite short.

Thanks for all your help. I will take your advise and not do the overnight train but rather stay an extra night in Budapest. Just to clarify that it should be okay if we just book the train seat reservations as we go?????? or should I try and book them before? Thanks again

Personally I acquire my reservations before travelling, but with one exception (A German ICE from Frankfurt to Brussels) there have been no full trains, so reservations on the day would probably have been OK.

As far as I know the main operators who have quotas for pass users are Eurostar and Thalys and the SNCF/RENFE service from Paris to Barcelona.. SNCF TGV in France has a 2 tier charging system - early pass users pay 10 euro, at some stage it reverts to 20 euro until all seats are reserved.

Hi can you please give me a step by step on how to reserve just your seats on the trains. I have tried to book Paris to lucerne and there is no where I can see to put in our eurail pass. They want to charge the full amount. Also do I choose the 1st class option if we have 1st class eurail tickets. Oh my gosh I am very challenged need pictures drawn I think  

There’s no train from Paris to Lucerne! If you give us the journey you want dates and times someone in the community will help

Firstly don’t panic  - we have all been there.

Unfortunately every source has a different method of advising them you either have a pass or want a seat only.

Also many of the operators and commercial sites do not facilitate online purchase of rail pass seats.

There are guides elsewhere on the community but for extra guidance we need to know which route you are looking at and which reservation tool you are trying to use.

It is also worth noting that there is a need to understand the difference between a multi train routing and a single train booking. So, as a previous post says, there is no single train from Paris to Lucerne so you cannot buy a reservation for the full journey.

You have to split the journey and source the reservations for separate trains - sometimes requiring different sources. e,g for Eurostar you use either IR or b-europe, but for TGVs in France you need a different page of the b-europe site. Both of the b-europe sites for E* and TGVs are specific for pass holders.

The Interrail web planner (find train times), although not perfect, is a good place to search for routings and which trains on a routing either need or offer reservations, but on multi train routings you need to open the routing to see which trains have reservations needed and which don’t.