Ghost Town at Sundown: Echo from the Past

So, it looks like Slim was the one who wrote the book that took Jack and Annie to the old west.
And he dedicated the book to them.
Also, Lonesome Luke’s song at the end of the book is sad.

Ghost Town at Sundown: Lonesome Luke

So Jack and Slim got away.
Where’s Blue Canyon? (Also, I’ve played the Nancy Drew games so many times, I keep wanting to call it Blue Moon Canyon.)
And now the horses are all OK.
And the ghost that was using the player piano and helped Jack escape the rustlers was Lonesome Luke.
Apparently Luke kinda lost it with grief after his girlfriend left him because living out west was too hard for her.
OK, so Jack was so tired he didn’t get to finish his notes or take off the cowboy boots that were hurting his feet so much before he passed out from being exhausted.

OK, so they finally reached the rustlers. Annie’s staying with the colt while Jack and Slim are confronting the rustlers.
When Slim’s like “OK, here’s the plan,” Annie’s like “OK, cool,” but Jack’s like “wIt, what?”
Now Slim’s like “this is far enough for you,” and Jack still has no idea what’s going on.
Oh, fun. Slim’s got the horses, but now the rustlers are shooting.
So, like, a ghost or something is distracting the rustlers?

OK, so this is the guy who initially herded the mustangs, and the rustlers stole all the horses.
So, this dude’s called Slim, and he decided Jack’s Shorty and Annie’s Smiley.
“How’d you two get here?” “Uh… a stagecoach… that we accidentally told to go to the wrong place…”
Sure, Jack, confronting the rustlers could be dangerous, but this is a kids’ book. Nothing bad’ll happen to you guys. Listen to Annie. That’s how you’ll find the riddle answer.
OK, yep. Time to go track down the rustlers.

So, apparently these horses are wild mustangs that the thieves or rustlers or whoever caught.
Of course Annie already figured out how to handle the colt before Jack could look it up because she’s great with animals.
Seriously, Jack. Listen to Annie. Reuniting the colt with his mom will help you find the answer to the riddle.
OK, who’s this new dude, and why does he think Jack and Annie are the horse thieves?

Oh, wow, so the town is a ghost town already? Even though they just traveled to the past? Must not be much silver or gold around there anymore…
Not sure on this riddle. I have an idea, but less than I did last time.
OK, so it was the river that dried up and everyone left.
And there’s more of the rabbits Morgan sent.
And there’s rattlesnakes everywhere.
OK, so there’s a calendar in the general store from 1878. Two years before the town was abandoned, apparently?
And now they’re trying on some cowboy outfits.
OK, but who’s playing the piano in the middle of a ghost town?

OK, so, Annie’s like “hey, that rabbit looks funny. Maybe we should go see if Morgan is telling us to go to the treehouse again.”
So yeah, Morgan’s there.
And now she’s sending Jack and Annie to the Wild West.