Until a week later.
She practices sorcery for hours a day, intent on exactly one thing: Lowering her weight to the point where she can use bluestream's method of flight to move like an arrow in any kind of harmonics. When she gets to the point where she can do it reliably, she commissions an elaborate pair of semi-metallic butterfly wings that will pretend to carry her but not actually support her weight.
Finally, she gets the necessary books on stone circles and studies up. By this time almost three months have passed. She steps back through the portal and goes to visit Promise.
She listens for life-forms, finds where Promise is, and goes there. "Hello again, Promise! It took a bit of an adventure and some weird political nonsense, but I got my hands on the books I need to make you a stone circle."
"Hi! That's good news. That stone you mentioned, you have some of that?"
"Unfortunately not, at least not yet. It comes from a certain quarry hundreds of miles away on my end and buying or trying to steal some would be too suspicious. I'm hoping I can find something close enough here and transmute it."
"I'll have to wander around and investigate some rocks, find one that's already close. You're better at sorcery than me, if I give you the books maybe you can get it easier. By the way, I decided to pretend to be a fairy. I'll be doing magic anyway, better to pretend to be a fairy sorcerer than a fascinating mortal-with-magic. Do I look fairlylike enough?" She spins around, the dozens of pockets on her pants and coat-with-wing-holes rustling like paper.
"You don't look like a mortal, anyway. Fairies might want to know what kind you are."
"Should I make something up? Do fairies all know what kind they are?"
Hmm. The wings are metallic. "What if I claimed I was an ironwing? Is there already a kind like that?"
"Not that I've heard of but I don't know all the kinds. It's a plausible name, anyway."
"I'll go look at some rocks, then. I'll probably want to explore a little, if rock from this forest is no good, rock from another part of the forest is probably also no good. Don't worry if I'm gone for a while - I've gotten pretty good at combining bluestream stuff and basic sorcery, and I've got like a month's worth of food in these clothes."
"Okay. Make sure your food's stashed carefully, though, someone could sneak something into it while you sleep."
"Sealed packages all. If it's got a hole in it, I won't touch it, and I can tell if they sorcered it from the eddies' aftereffects."
"Sounds good. And - probably better to leave a fairy's territory if asked rather than get into an attention-getting sorcerous fight. You don't want the Queen's attention."
"If I'm on someone's turf and they want me off, of course I'll leave. Who's the Queen?"
"...Have I not mentioned the Queen? I haven't, have I. The Queen is a one-of-a-kind fairy whose kind magic is to know the names of every fairy that exists. She wouldn't know yours, but she wouldn't need it; she has her pick of all the best sorcerers in the world and more who wouldn't need sorcery to threaten you."
"Oh my. Yes, that's to be avoided, especially since she'll be wondering why she can't find my name. I can fly six or seven times as fast as River now, if I really push hard - What would you give my chances of escaping long enough to find a gate to somewhere that isn't fairyland?"
"I don't know. I've never tangled directly with her court and hope to avoid it indefinitely. Actually, once you've bluestoned me, if it works, I'm probably going to take a cutting of my tree and move to another continent."
She flies out at a brisk pace in the opposite direction from River's house, landing to investigate the stones of each new biome.