I think it would be incredibly foolish to arrange a tour now. A video with a big youtuber is guaranteed to bring a lot of people in and if you want a sudden peak in population that's a good way to do it, but they need a reason to come back tomorrow if you want a rise in population. There's no big event right now to build hype, Gondor is mostly done, it's just little bits that most people aren't going to be interested in. You need to time this well, there will be sweet spot between Gondor and Mordor when there's hype for completion of Gondor and hype to get involved in building Mordor (and Moria I suppose), that's when you want the video to go out. MCME's population has declined since the golden days I suspect largely due to moving away from literally everything being done by hand (there are no people sculpting cliffs, grassing huge swathes of land in Rohan, or sloping hills in the Shire anymore), if you want to keep people involved you've got to do things like build competitions (The Meduseld build competition was very exciting back in the day) and texture competitions and try to get some hand terrain work going on (are river digs still a thing?). If you're not going to do that you need to find some other activity for people, pvp is always good, as are the races that take place in the events, and of course the tours which were once a staple of entertaining on mcme (congratulations to @Glinting on getting promoted to the best rank). You could think about reintroducing NPC's, I don't remember why they were removed but we had them back in 2011 and they're always nice to have, you can give NPC's messages so perhaps set up another scavenger hunt or some kind of mystery and instead of having clues with the signs make people go find Faramir in Henneth Annun and ask him, or Barliman Butterbur in the Prancing Pony. Make it a challenge and you'll keep people on the server and exploring looking for NPC's to talk to.
If you rush a youtuber in now and the people come in and don't stay, you're buggered, that ship has sailed. Wait a bit longer and do the tour when you've got incentive to stick around and you'll be better off in the long run.
If you rush a youtuber in now and the people come in and don't stay, you're buggered, that ship has sailed. Wait a bit longer and do the tour when you've got incentive to stick around and you'll be better off in the long run.