I dunno, I found DoL to be pretty messy. I think a lot of that has to do with the fact that the devs have to bend Twine/Sugarcube to their will in order to make sure that it doesn't break and lose its state.
^ This.
It's not really worth the risk to continue LT, IMO. If it were under a proper FOSS license, sure, but continuing it as-is opens you up to the potential for C&Ds. I think you'll also be more likely to find people willing to contribute, given how much of a mess LT's code is. Refactoring it would take just as much work as starting a new project, as much of the rough bits are buried several layers deep.
Also, for the love of $deity, make sure you know how to 1) code, 2) structure projects, and 3) plan projects
before tackling something like this.