That sounds fabulous, but it's a bit incompatible with a 1 week holiday if you don't want to view sitting on a train as "a holiday".
The purpose of travelling for holiday is not always sightseeing. Sometimes (for me, most of the time) it's about what's at the destination and what you do when you get there. For example, a sporting event, a particular sporting or leisure activity etc.
Well, I don't spend my holidays on the train. Like I say I visit places on my way to my destination, which is usually the Greek island of Corfu in the Ionian Sea. So for example, the summer before the Covid winter I spent a couple of days at Bruges, then Lille and finally Bologna, before taking the ferry from Ancona to Greece.
On the other hand, I've also travelled by bus (no good trains) to go to a conference in Plovdiv, Bulgaria and I'd have also travelled my usual way to conferences in Athens and Rhodes this year, that got cancelled because of Covid. Like I say above, you can do this kind of thing at a leisurly pace, or you can do it fast.
But I think the real problem is that travelling like that limits your range. I was offered an exchange position in China but travelling there by land would have taken me a week or so, so I declined.
But I can accept that my options are curtailed this way. Air travel has spoiled us in that we take it for granted that we can travel to the other end of the world in a few hours any time we like (if we can afford it), but this luxury has cost us greatly in terms of environmental damage. So, personally, I don't accept that going at a sporting event or leisure activity trumps the need to reduce emissions from air travel.
So, to rephrase my original comment, above, taking a holiday doesn't mean you have to go around the world for it. You can holiday closer to home. So I won't get to see the Fiji islands? I can live with that. We're not going to get out of the mess we've done and still enjoy our way of life, one way or another (the "other" being that eventually climate change will make our current way of life unfeasible anyway; for example, Fiji will sink under the sea).
People have to come to the conclusion that there is a gap between what they want, what is currently allowed and what is sustainable. The fact that something is economically viable doesn't mean it is ecologically viable.
The purpose of travelling for holiday is not always sightseeing. Sometimes (for me, most of the time) it's about what's at the destination and what you do when you get there. For example, a sporting event, a particular sporting or leisure activity etc.