So I've got good news and stressful good news.
The regular good news is that I ran the quickstart for my friends and they loved it! They weren't impressed with the dueling rules but they were glad to hear they wouldn't be kept in the final version.
The somewhat stressful good news is that they loved it so much that they want to keep on playing. Luckily they want to keep on going with the premade characters so I theoretically can just keep going with the quickstart rules and supplement it with info from the 1st edition PDFs when they're released, but right now I just need to come up with something.
They ended the game by beating the swordsmaster (partially due to a misunderstanding of the dueling rules, but I'm not about to retcon the fight because of it.) But given that I don't know anything about the Sarmatian Commonwealth beyond what was told in the quickstart, I'm not ready for them to return there and retake the Prince's throne. It sounds like the Prince's player probably won't be able to keep playing though, so I thought it might be a good idea to delay their return by kidnapping the prince.
Anyone have any ideas of where I could go from there? They're currently in Vodacce, but I wouldn't be adverse to them having to go to somewhere close by like Castille or Eisen.
Shipwreck.
Put them on a boat headed towards Sarmatia, and have a storm send the boat off course, then crash it into a reef. The PCs could be the sole survivors, or perhaps you have some mooks along for redshirting. They'd have to figure out what they can get off the boat/island to survive and set up a beacon for other ships to rescue them. You can have a few random adventures on the island-- perhaps it's close enough to Ifri that there are gorillas or lions, or perhaps a bottle with a map in it is found on the beach or there's some ruin to explore. And once you've gotten the 1st ed pdfs and have a chance to read up more on the commonwealth, you can have them get rescued on go on their way again.
Lots of adventure hooks abound in a shipwreck scenario. =)
I'm sure there are other options you could take too.
Who did they end up getting backing from? A few of those people had readymade adventure hooks.
“Every normal man must be tempted at times to spit on his hands, hoist the black flag, and begin to slit throats.”
- H.L. Mencken
So many options....
When you get the 1st ed stuff, Think about using the Tangled Strands adventure. It would be a pretty easy conversion and it was a fun adventure.
Personally, I would put them on a road trip to various nations to gain favor as well as commitment to not recognize the Sabat lead government in Sarmatia. Dealing with people like Hainzl, Fischler, The Gaius, Bernoulli and Lucani in the immediate area. as well as the Vendel League in the distant but important trade routes. Any or all of them could need to be coerced to the heroes' side via completing quests or favors for the NPCs.
Depending on the exact political situation, I agree that a sizeable contingent of soldiery setting out might be problematic. It seems unlikely that Sabat acted alone and exclusively domestically; the hostile takeover of a kingdom is usually something with international repercussions and Sabat likely had, at the very least, assurances against instantaneous invasion. The group would likely have to bounce from court to court to court, assuring the various powers that Vodacce has no expansionist ambitious (a tough sell, as Vodacce is all about ambition), securing support, and ferreting out Sabat's allies.
Depending on your plans for the scope and scale of your campaign, I would consider the Emperor of Montaigne as a possible mastermind. The ancien regime of absolute monarchy is in decline and it goes without saying in our own history that the modernizing forces which spread across Europe cost an emperor or two their head. Perhaps the Emperor is attempting to stem the tide. Conservative elements within Ussara, which would want to prevent anything resembling an egalitarian system on their border, might make for another good culprit. Additionally, Sabat's little coup or an attempt to undo it might be the flashpoint that sets off the powder keg of Theah's politics without some timely intervention by the heroes.
If your group is more interested in combat and the number of troops is limited, you could have a ship with soldiers waylaid by Sabat's mercenaries or privateers at sea for an exciting naval battle.
“Every normal man must be tempted at times to spit on his hands, hoist the black flag, and begin to slit throats.”
- H.L. Mencken
I ended up going with running the first two chapters of the Tangled Threads adventure like Salamanca suggested, threaded as them going on a diplomatic mission to San Theodoro to gain the support of sympathetic Castillian lords, while dealing with each of the first two chapters before and afterwards.
We all had a blast, and we're just going to keep on riding this train until Summer Break comes around. Probably try to run them through a couple of homebrew adventures in Avalon, and Eisen before I put them through the next chapter of Tangled Threads. Winning Hainzl's support sounds like it could make for a fun adventure.
Thanks for the advice everyone!