I've never really looked very far around this Forum all that much - it seems to have an almost endless supply of subjects, many of them very interesting. I'll try to resist getting involved in too many threads, but this one makes me think of a couple of personal trips to do with not flying, which may or may not interest others.
A few years ago my wife and I had a Christmas present from our son, which was Eurostar tickets to Paris. I thought it might be interesting to use them for a day trip, which was quite a challenge starting in Shrewsbury, but we did it. We left Shrewsbury just before 05.30, and arrived into Euston soon after 8.00am, in time to walk to St.Pancras for the 09.31 to Paris. Once there we caught the Metro to a superb bistro restaurant near the Seine where we had an excellent and leisurely meal, before heading to the Sacre Coeur for a look round, and then to the Gare du Nord. Back in London we had enough time for a quick drink at the Doric Arch, then back to Shrewsbury just after midnight. Yes, it was a long day, but starting and finishing in our own bed from Shropshire to Paris without using any flights did leave us feeling quite a sense of achievement!
Inspired by that, the next year we had a short holiday in Andorra. We travelled to London in the morning, then to Paris in the afternoon, and then the sleeper train from Paris Austerlitz to l'Hospitalet, where there is a connecting bus through the Pyrenees to Andorra. We had just one night there, but it did give us two full days since we arrived soon after breakfast time, and didn't need to leave until late afternoon, to catch the sleeper train back to Paris. This meant that we left Shropshire without any need to get up early, and arrived back home in the afternoon just three days later after two full days in Andorra, all without using any flights. On the return trip we had booked the 10.13 Eurostar out of Gare du Nord, thinking this would allow plenty of time for breakfast after arriving on the sleeper train at 07.20. What we hadn't bargained for was arriving into the opposite side of the city centre of Paris 2h20m late, but that's another story ...