Scrivener of Doom
Adventurer
(snip) I hear TOEE becomes a slog after a while and most groups don't finish it. Give up when it stops being fun, and retire the PCs with their XP as the "high score" to beat next time you play AD&D.
ToEE is one of those adventures that, to really sing, needs a lot of DM intervention.
Most of the dungeon areas feel like a collection of random encounters of steadily increasing hit dice (which is essentially what they are) rather than feeling like a clash with agents and servants of elemental evil. Frankly, if the title didn't mention "elemental evil" you would really struggle to conclude that that was the dungeon's theme.
As for the nodes, they are the most incomplete parts. They literally are incomplete and the DM is left to actually stock them.
Honestly, keep T1 and then rewrite the rest, maybe keeping a few of the key set-pieces for flavour and as an homage to what T1-4 could have been if it has been properly designed and completed before being published.