DS is 18, he's going inter-railing in the summer 6 weeks or so all in, with 5 friends.
Last night he was talking about his itinerary, they have decided to pre-book all their hostels as apparently it's not uncommon in some places to be unable to get a room.
In the 48 days I think it is they are travelling they have booked for 20 different cities. They aren't doing any massive travel days but some are more complicated than others (like getting from Lake Bled to Trieste or having to get a boat across Lake Como to get to the hostel) but generally they aren't travelling more than 4 hours in a day and there are quite alot of 1/2 hour journeys like Venice - Lake Garda - Milan, Lausanne - Geneva etc.
DH thinks they will be exhausted, I think yeah they probably will be but it's not our business and leave them to figure it out?
They are staying 2-3 nights in each place (maybe one place is a one night stay but I think it's because of trains).
AIBU thinking it's not our business and we shouldn't warn him? Or should we suggest they change it up so they aren't moving so quickly all the time.