The C64 reverse engineering covers that a bit. At least regarding general data structures, as opposed to in-depth Apple II hackery (you get some C64 hackery instead, of course).
Ok, that is the craziest (in a good way) thing I've seen in some time. I'd have thought PoP had been ported to the C64 at the time - Karateka was ported just about everything. So in 2011, starting with the Apple source, disassembly dumps, graphics from a free version, looking at the PC port and god knows what else, someone ported it to the C64. Amazing.
EDIT: Oh, and apparently the Apple ][ source hadn't been found again yet, making the thing even more bonkers. Mechner's comments here:
If I remember correctly, the ported game does need a memory extension, which would've been a no-go back then. Wonder how much you would have to cripple the ported effort to fit in in there, if at all possible with the same approach...
Yep, it looks like it requires a 128KB Apple //e and up. In the comments of the blog, Mechner mentions he couldn't get anyone interested in porting it to the C64 at the time as the system was considered too old. I guess by '89, 128 KB Commodores weren't considered that interesting of a market.
The original must have needed all the memory it could get its hands on - looks like it doesn't use the Apple //'s 'double high res' modes, for instance.
Forum thread of Sanglard trying to sort the thing out, with the help of some 6502-heads is also entertaining:
Almost makes you want to combine the two actually hacker-ish posts of the last two days - the lightweight block ciphers and this and burn a weekend implementing SIMON in 6502 assembly. Almost.
EDIT: Oh, and apparently the Apple ][ source hadn't been found again yet, making the thing even more bonkers. Mechner's comments here:
http://popc64.blogspot.com/2011/10/prince-of-persia-for-comm...