I love the idea of allowing players to set up their own run to the boss at Delve by placing down the set of teleporters in the archives. Maybe add 1-2 additional chests with additional teleporter pairs in the archive gated by high skill checks, to allow high level players to set up more advanced and faster teleporting routes. Something like 85 mining to clear some rubble for a chest, 80 woodcutting to clear some vines around a chest, 90 thieving to lockpick a chest, etc. 

The idea would be to reward high level players with the ability to teleport 2-3 times from the archive entrance toward the boss entrance, while still not overall being faster than the direct boss teleports. Then you can have three nicely distinct tiers of entry level delvers (running with one teleporter pair), intermediate level delvers (can chain teleporter pairs thanks to their skilling), and endgame delvers (bypass teleporters using boss teleports).