Eru Ilúvatar is not inclined to be helpful.

'The ends justify the means' never quite sat right with her. Its cousin 'suffering now, benefit in the long run' is only slightly better.

But both of them are better than allowing such a powerful being who has crossed the line several times over to just keep on finding new lines to cross. The long run is worse off with Melkor in it.

She goes back to the elves and apologizes for her foul mood and abrupt departure, and finishes the foundations and asks if anyone would be willing to teach her the local magic, probably as a trade and hopefully as a start to a less tense working relationship.

The Elves like teaching their magic! Does she eat? She's welcome to come in and have something warm to drink, if so, and get the lecture...

"I do eat, though I don't necessarily have to. Thank you. I might like to give a lecture of my own, once I have a better idea what of my knowledge is new and useful to you and - safe to experiment with."

"We'd enjoy hearing it." And they describe how Elves do magical items, in more and more depth as she demonstrates conceptual understanding. 

She sips whatever hot drink is on offer and takes notes in very small script on thin slate tablets. She seems to be leaning heavily on a different set of concepts for analogies, and admits that her sort of magic does not appear to work in this world, which is rather a shame because it appears to be easier to learn- though somewhat less tractable to producing arbitrary results with enough effort.

There doesn't appear to be an elementary display of magic she could manage in a few hours as a proof-of-concept, so she probes for likely fields of knowledge that she would know enough about to give a lecture on. Civil engineering, waterworks, and the art and science of building things, perhaps. Or metalwork, or chemistry, or mining, or biology, or languages and her world's history if they want interesting over useful though perhaps that category ought to wait.

They would love lectures on any of those things though are sort of overwhelmed with tasks, having newly arrived on the continent. 

In that case, she thanks them for taking the time to give her an introductory magic lecture and hopes that her construction has made the tasks number somewhat less. She will leave for now and think about what to lecture on and perhaps be back in a few days.

Lovely! The other host, are they safe wherever they are?

"Last I checked they were safely walking along the stretch of road I made for them. No Orcs for hundreds of miles, and no terrible danger from the cold. I believe they plan to settle here." Mental impression of pointing at a spot on a map.

"Thank you."

And off she flies back to the north. There are other visibly populated areas, right, she should probably visit those eventually even if there will be language trouble if they're not elves. She knows a small but decent amount of - whatever this language is, she doesn't even have a name for it...

How are the north-elves doing?

They are crossing the road with supplies and all due speed!

Lo, the end of the road which they were fast approaching gains another two miles before she swings down and casts her mind out to ask, Hello. Before I produce more carts, I'd like to know what design flaws you've discovered in the prototype. Because there are going to be design flaws, that's just a fact of engineering.

They do have some suggestions, presented with more confidence than any of their other requests of her; engineering is different that negotiating with mysterious powers.

Some requested changes insightful, some are reasonable, some are problematic and she lands to produce sketches and explain how and why - the chain would be subject to shear stress if she did that, the roll-bar could be liable to attempt to occupy the same space as a pedal in sharp turns if... Actually it already does that, any suggestions on how to make it not?

(This is fun)

They're also tremendously enjoying it, and the suggestions get more confident and more parties involved.

Soon they will have a very elegant set of sketches for bicyle-cart thing mark two. She keeps two sets of plans evolving alongside each other - one tooled for being easy for her to make and another meant for people with less innate control over metal. The constraints contrast interestingly. Her natural inclination in engineering leans towards extreme durability, the kind of thing that ought to keep working flawlessly for centuries as long as nothing too far outside the intended use case happens to it.

She might be dragging this out a bit, continuing to refine well after it meets her approval for what was supposed to be a very quick project - but it's relaxing, and a good chance to actually get more familiar with some of the people involved here.

It is pretty stabilizing to do engineering rather than politics; he thinks it's good for everyone on their end, too. Perhaps she can do this for Fëanor. Perhaps he'd find it therapeutic.

Possibly but who even is Fëanor, this person who she had known as Maedhros?

At any rate, this particular engineering project is sufficiently done for her to decide to produce thirty carts. She intends to leave the first one as-is, as a relic, unless someone wants it updated.

They'll keep it, put it on a pedestal once they have a nice city on the other side. Thank you.

Since with these carts they are no necessarily longer limited to the pace of their slowest walkers and supply-haulers, she paves a long stretch of road, gently sloping up and down or forming bridges to deal with cliffs and rifts.

...She kind of wants a break from talking to these two warlike bands, even if engineering is relaxing. So she takes a tour of the continent, flying at supersonic speed perhaps two miles above the surface, refining her map and trying to identify any populations she hasn't interacted with yet.

There's a forest that's hard to look at directly, there are walled cities along the coast. She's not going to be able to see aboveground signs of the Dwarves.

Well, her world-sense extends a few miles in a sphere around her. It's not inconceivable to discover them if she is lucky enough to fly directly over a Dwarven city, but for now she still does not know they exist.

The repellent forest is interesting, potentially worrying. It's the same sort of thing as Valinor's ward. She investigates the walled cities first, slowing to a stop several miles outside one and trying to project vague greetings.

This makes the people of Brithombar, who've only just broken the siege; very anxious; they gather armed on their walls, and ask Ulmo what's going on.