I really like the rest of this adventure, so far, but to me the Scribbler's Rhyme is very misleading and just doesn't work very well.
"On eastern shores of steaming mirror,"
The first thing that I thought about, and the first thing I think my players will think about is the sign you see when your coming into Sandpoint. The sign being a mirror saying "See yourself as we see you." I thought this sign was very interesting, and when I read the rhyme I thought OHhhh that's cool. But the rhyme is referring to a lake. =\
"Where seven faces silent wait,
Encircled guards at Runeforge gate"
First thing I thought of was the seven stones inside the Sandpoint cathedral. Another thing that has been emphasized throughout the adventure path that seems to have a purpose with this rhyme, but the rhyme is talking about seven stones in another place.
I really liked the idea of using things the characters have seen around town in this rhyme so the players can use the things they have learned along the way to solve it, but this rhyme does not offer them that, instead introducing new things that have not even been hinted at before. I can imagine my players running on a wild goose chase to the cathedral and the Welcome to Sandpoint sign, and then after rolling a knowledge check, me telling them about this lake and stones outside of Sandpoint.
Pretty disappointing.
It worked better for my game to have the standing stones that led to Runeforge be the ones in Sandpoint. I lost the dragon encounter that way, but I'm not missing it particularly.
I thought the rhyme was weak, but for us it didn't matter because the PCs bargained with Xaliasa to send them to Runeforge as scouts. (He was thinking, "They'll come back beaten up and I can take their stuff." They were thinking, "We'll come back two levels higher and trounce him." They won this argument.)
I'm in favor of tying things back to Sandpoint when possible, and this one was pretty easy. It led to a fun interaction with the hellknight investigators after they returned to Sandpoint, too.
Mary