There is a kind of mechanic I was considering for using for long-term playbooks, especially the savvyhead, that I never got to try but might prove useful to you.
I'll write in terms of the savvyhead because that's what I thought most about, but I believe it should work well enough for the hardholder, too.
Basically, it's a kind of reverse front - you start at the basic proof of concept, then make a prototype, and then you make the actual thing which in turn makes a big splash in the world.
Say you're a Savvy, you want to take control of the tornados that ravage the land. First, I ask - is that even possible? How? The Savvy needs to do something concrete that tells me that he can pull this off - maybe he tries to take a chunk of the maelstorm and manipulate the winds with it. If that doesn't work out somehow, that's it, the question's settled - no one in the setting at hand can control the tornados. You might be able to cope with them by hiding or building shelters, but control is downright impossible. The game is now about how you deal with this.
But say the maelstorm thing works. Then you have to actually make a machine that controls a real tornado and test it out. If the best effort to do that doesn't work - the crucial machine part is destroyed, lost, or goes out of control, that's it - this is now a world of hope and possibility, but not the ability for actual change.
Finally, if it does work? Well, what does it mean to be able to control tornados? How is this ability used? Are you really better off when your best efforts come through? The thing you made is now recognised and used by the community, and you deal with the ways it does so.
Is this different from what you normally do as MC? I think it is. The problem with these kind of long-term fictionful character arcs, like making a thing that controls tornados, or building a society on a vision, are based mostly on the fact that the MC allows it or not. Can you control tornadoes? Are your insights into what would make a community work accurate enough to have even the chance to work?
If you don't get that assent early in the game, the game becomes about something else, which is well enough. More worryingly, actually getting that assent might mean that the game is no longer about a question of what your character can do, because you've already settled that question, implicitly or explicitly. Is a Lockean post-apocalyptic society viable? You already know.
Not already knowing but being able to find out is valuable, I think. If I was a braver man, I'd even say it's necessary to have anything worth calling a game at all.
So the idea is to set yourself as MC a kind of explicit framework of questions that controls what's possible in principle in the game you're playing, and develops that through the success or failure of player actions.
Is the idea proposed possible in principle?
If yes, is the idea proposed workable right here and now, with what you have to work with?
If yes, what are the real, concrete, longterm or wide-spread results of what you just did? Is it really the thing that you wanted?
Specifically for your case, I'd just let the Hardholder do the trading mission as soon as possible, think about all of the things that could make trade completelly impossible, have the Hardholder deal with (or accept) them, and see where it goes from there.
Of course, you know your game better, so it's really your best guess whether the trading thing is something the Hardholder is putting great hopes in, or if there's something else interesting around.