MadameCurie I used to finish events in a day or two while I was in Scandinavia, too. Now that I'm in China it takes me longer, at least 4 to 5 days, sometimes up to a week, depending on the size of the event, but I don't mind. And I still finish the story fast, it just takes longer for the challenges, because they're the costly ones.
But, despite the bigger tile cost, you should take into account that not only you get better equipment, but your quests & clear out bonuses are bigger, too, so you'll level up faster. And the recipes in the kitchen are better, too. There are pretty good awards later on: for level 200 you get +300 reg, for level 250 is +350, for level 300 is +400. I know it seems far away to you now, but the postcard events with their 10x exp bonus are great for leveling up. I always level up at least once during these weeks. I'm level 275 at the moment, so now I'm working toward the level 300 prize.
Also, I should mention that I haven't spent any real money, there's enough gems as awards. I've spent so much of them on equipment, weekly boxes & stories.
Anyway, when I started playing I didn't know anything about strategy, I just kept playing, once I realised I need to clear out my camp, that was my #1 goal until I did that, and I think went through Egypt unintentionally fast. I started playing in Sep/Oct 2019, and by the time the Xmas 2019 event came, I was already in Scandinavia. As for Scandinavia, I wasn't in a hurry, only toward the end of the region I decided it's time to get out of it, so I applied myself to clearing out the region & finishing the quests so I can progress to China. Then I applied myself to clearing out the China quests needed for the China mines to open. Now, I'm not in a hurry, I just play relaxed in China in between events, and I absolutely love playing in this region. I don't like to rush & I like clearing out everything, because I found it annoying going back in Scandinavia to clear out the locations.
Anyway, there's both pros & cons whether to progress into a new region. You probably won't be able to play as long in them because of the tile cost, but that's why I save up my food, for when I feel like playing more. And as others have said, investing in clearing out the camp, the equipment & the switch system are pretty good tools.
Sorry for the long reply, I tend to forget myself...