Looking for a good adventure for a party of about level 14. The setting is FR, and the edition is 5, but I am happy to adapt content. I like "unconventional".
Yes, in fact the original tomb is used as a portion of the adventure itself (the boxed set included a direct reprint of the original module). I'd use the toned-down 5th edition version; I think the module would work better with that instead of the frequently-unfair original (as you definitely want the party to survive to get to Moil and the Fortress of Conclusion.
There is a very large overarching storyline now before you get to the core ToH. And then there's a post-Tomb adventure which is quite dangerous in the City of Moil.