I know flights are usually cheaper (unfortunately, when you look at the CO2 emissions), but I like to take the train from time to time. Last time I did Barcelona - Madrid in high-speed-train, that was quite nice.
Sweden is so bloody long. I’ve gone to Norway and Denmark by train. Denmark by train was roughly the same time as flying, including transfer etc. Too far for any other country really
The trick is to catch a sleeper train. Have a full day of work/leisure, board the train, sleep, and wake up at your destination in the morning.
The Stockholm-Copenhagen journey is short enough that they park the train somewhere in the middle of southern Sweden for an hour or two to make the timing more convenient.
To neighboring countries yes, if there is a good connection. If there is a night train even further. However, the price should not be much higher than a flight and I want to change train as little as possible. Buying tickets should not be too complicated either. Unfortunately, taking an airplane is often easier in my experience. We need a true high-speed railway network across Europe. Something like the Shinkanzen.
I personally don’t use trains, because there are no reasonable connections on the routes I frequently use. Also, trips by train (especially when it’s cross-border), are often more expensive than the corresponding flights.
One of my dream vacations is to get my wife and kid Eurail Global Passes for a few weeks or a month, and just backpack everywhere constantly staying in hostels and seeing everything. It’d probably be kind of stressful and tiring, but memorable.
I’ve never done that, exactly, but I’ve done several trips of that length around Europe and South America.
My (general) sanity rules have become these: never stop for less than two nights, always spend four nights in the same place after 2-3 shorter stops, and spend a full week somewhere during the trip.
While this may feel limiting, I’ve found that anything more strenuous has always overwhelmed someone in the group.
Edit: minor schedule adjustments
I’d say: do the opposite! Don’t plan anything, stay no more than two nights at the same place, jump on a train and see where you end up. Then, if you don’t like, just take the next train somewhere else.
I did this twice in my early twenties and it was amazing. I mean, it was absolutely horrible. I slept on bark benches, in Cafés, in train stations, before train stations (until they turned on the sprinklers)… I was picked up by the police because we got lost in a field and more than once I was convinced I’d die. But it was absolutely worth it and both trips became core memories / PTSD trigger.
But seriously, don’t follow this advice if you have a kid and are not an immortal twenty-something.