I've been thinking about this, I think the text you suggested would be a good idea. Like you said, I'm in a weird place because I got good at the game before quests were even introduced, so I don't really have the proper experience--I'm trying to power through the quests because I want to see what they are, so something like this that gets in my way feels awkward.
I have another idea, and maybe this defeats the purpose entirely (trying not to play backseat game designer here) but I figure I'll suggest it anyway. Maybe you could streamline the quests, but find a way to mechanically emphasize that getting to the top is more important. Like, if a player regularly makes it well past the teleporter quest block they're working on, they could skip straight to the next block. Like if I'm working on the Jungle teleporter but I've already made it to the Desert a dozen times, let's just skip ahead. This is sort of similar to the approach Spelunky had with teleporters. Does that make any sense?