Earlier today as I was thinking about my mind maps, I noticed something:
Photoreading is a lot like doing those 500 piece puzzles. The puzzle basically tells you what the puzzle will look like, and that's much like previewing and thus looking at the entire book as a whole. The PRWMS emphasizes moving from whole to parts, and that's precisely what happens when making puzzles: We can start by simply attempting to put pieces together without first seeing the big picture.
Once we see the big picture, some of the colors fit together, much like the way activation allows for the pits of information to come together. Seeing the big picture also allows us to see the colored pieces that do not belong with other pieces. The same is true with activation in the sense that we can simply superread over those unnecessary portions (which most likely do not fit our purpose), or come back to them at a later time which is precisely what I normally do with 'strange' puzzle pieces.
I know this isn't the best analogy, but this seemed to help me as I was trying to explain it to a friend.
Additionally, here's something else I've thought of:
Mindmapping reminds me of cartography:
The book (or chapter, article, etc) is the territory, and mind map is the map we use to navigate through the uncharted territory (i.e. the text). It's probably best to first get a general idea of the overall features of the map, just as the PRWMS emphasizes 'whole to parts'. Once the whole is understood, the details can be filled in via activation since comprehension comes in layers. Each 20-30 min activation pass through the text would give us more details on what belongs on the map, and the more passes there are, the more charted territory we'll cover. In other words, the mind map will become larger and with more fine details over time.
Once the mind map is more descriptive, passing through the territory via rapid reading would then verify the content of the mind maps.

Now of course, this analogy is not perfect, but this helps me.
Hopefully, it helps someone else

Sincerely,
-Jason