You don't need to plan anything in advance if you don't want to do that. The only limitation will then be the availability of any mandatory reservations, which can be a problem at busy times in France and especially Spain.
It also doesn’t hurt to check some of the possibilities in advance. Montenegro is only connected by rail to Serbia and Serbia is currently not well-connected at all (only to Montenegro and somewhat to Bulgaria).
It's okay not to have a concrete destination, but you do want to check train times from A to B no?Always advised to split up longer journeys. Don't check e.g. London-Kiruna in one go, but split it up in smaller stretches.
Don't rely to much on the rail planner app or planner from interrail. It only updates once a month, so it contains a lot wrong information. Use the national planners or the one from Deutsche Bahn.
Spain and France are not the most flexible Interrail countries. A lot of high speed trains with mandatory reservations, sometimes selling out. Alternatives are possible via regional trains, but take more time. You might want a bit more travel days for that.
Also, for the Eurostar you need a reservation. Best get them ASAP, as they can sell out.
Hi, no you don’t need a plan. But keep in mind that there are international trains to Montenegro only from Serbia. And to Serbia there are almost no international trains. Do you mean Montenegro the country in the Balcans? Because it is a bit weird in between of the other destinations France, Spain and Portugal.
BUT: in France all high speed trains need a reservation, and you need in the most cases to buy it some time before (in summer or weekends the trains could be sold out), same for Eurostar. In Spain you need almost for every train a reservation, and they can’t be booked online, only in Spain at Ticket Offices of RENFE, in Germany and Switzerland at DB and SBB and I mean one ticket office of CP in Portugal. Same for Portugal they do not sell reservations online, but I have no idea if there are trains with compulsory reservations.
If you like to travel without planing, then I would advice to travel in Switzerland, Austria, Germany, Belgium, Netherlands, Denmark, Czech Republic and Slovenia. There are almost all trains with only optional reservations. In the other countries, long distance trains could be affected by compulsory reservations, but almost no Sold Out. Local trains can’t in the most cases reserved. Just hop on.
Again- it seems this isolationist Brexiteers make everything complicated; as UK/GB you canNOT use EUrail, its INTERrail, which has the condition to only use it on 2 days In your own country- called OUT and IN days.
As above: again you have also chosen the 3 most pesky countries for making RES etc-€* is also even worse for that.
But black mountains (that is what Cerna Gora=MOnte Negro means) is also a well-known touristy a bit mountainous area in the So_We of Germany, bordering FR and Swiss-far easier to fit in this planned routing.
The country MoNe also has ferries to IT via Adriatic-payable, but can cut off many days f cumbersome travell in old vandalised trains also not well connected.
