Are there plans to expand the game to tackle other space adventure tropes that fit nicely into the “slice of category”? Space trading comes to mind as something that can have a nice rhythm but things can always can go wrong and the crew has to handle the bumps.

Not explicitly, no, but I have thought about it from time to time.  As solo RPG's go in the sci-fi genre, StarForged is pretty big, and that covers that genre pretty well, so it feels like it's not ground I need to cover, but it probably wouldn't be hard to kitbash Welcome Aboard, Captain to work with that type of genre:

• You could use the starship creation rules exactly the same.
• The crew wouldn't necessarily be specific officers for different disciplines (but they could be).
• The mission rubrics would have to be rewritten, but the objective creation rules and outcomes would all work as-is.
• All the ship functions would work as-is.
• If the focus is on space trading and smuggling, there would need to be some sort of economic model, which Welcome Aboard, Captain doesn't currently have. That would probably be the biggest thing that would need to change.  We'd need a way to track, acquire, and spend wealth.  I imagine it would be "mechanically adjacent" to Veteran Points, since the point would be able to spend them on maintenance and upgrades for the ship and crew.

So, for a quick kitbash, I would make these rule changes:

• When generating a mission, instead of an AWF mission, imagine it as an opportunity.  if the mission doesn't make sense as a thing you might find yourself needing to do (e.g., you're not going to be going on military incursions against Alliance separatists, probably) imagine the rolled mission as "something that's happening", not a mission assigned directly to you, and then think of an "angle" that you can use to leverage that situation to your advantage to gain wealth. Taking advantage of the rolled situation is now your "mission"; you need to complete the "mission" to get paid. 
• Unlike with the Alliance Wardens, you aren't always required to perform a mission that is assigned to you, so if it's not a surprise ambush or sudden emergency situation, you can take it or leave it and generate another opportunity, but each subsequent refusal reduces the wealth awards by 20%.
• Veteran point spends on ship functions and capabilities are no longer available.  However, you can spend Wealth points on these elements at the same rate.
• When a "mission" is completed, instead of earning VP, you earn Wealth, unless it doesn't make sense to earn wealth from it (e.g., surviving a disaster).  You can only spend Wealth when at a stardock with the facilities to enact the changes.
• The Alliance Lodestar is no longer in play; you don't earn Explore, Understand, and Unite points.  Instead, you choose three personal goals for your captain and name them accordingly, and measure your success after each mission in the same manner.  At the end of your career, you can measure them using the same rubrics, but imagine different outcomes appropriate for the personal goals you chose.

Everything else, I imagine, would be basically the same.  New mission rubrics could help make for better, genre-targeted adventures, but what's in the book would go a long way towards getting there in the mean time. If there's a lot of interest in such a resource, though, it's definitely possible to make a supplement to support it.

Hope this helps!