My batch of murderous goblins are sneaking into a city. Their goal is to get across town to the temple of Shelyn and assassinate the priests there. Is there an interesting/exciting way to handle sneaking through the city? My first thought is to throw down a big map of the part of the city. Goblins start here; goal is there. I could have guard patrols and random citizens in the streets. With plenty of cover in the alleys. But I'm worried that the entirety of this challenge will boil down to my players rolling really well on stealth and the NPCs having no way of detecting them. I could add a few dogs for scent but am I just punishing the players then for being really good at Stealth? Maybe add in random events and items to try distract them?
Or should I skip the whole thing and just teleport them to the temple of Shelyn and start the assassination mission there?
I would consider a few narrative encounters, which you can shape to the map depending on how they move through the city. If your gobbos are so stealthy that they can't be detected, then... well, they built the characters that way. Also consider if your encounters are interesting in their own right or if they are busy work for them on their way to the real mission. I'd probably run it as a node-based VP challenge: you build several general routes, with each node representing a different challenge that needs to be overcome. Once you have enough successes, you move on to the next node.
Maybe some can be merely overcome by stealth, but throw in other stuff: an alleyway that you didn't realize was blocked at the end requires them to climb a treacherous fence that needs to be done quickly as the guard start to approach, or a random drunk sees them and either needs to be killed quietly (and have his body disposed of) or bribed/convinced they aren't a bunch of goblins. Maybe a fire has occurred on one side of town, and with all the people in the street individual stealth is impossible; they'll have to either disguise/deceive to get across, scurry across some laundry ropes that cross the street, or possibly hope onto a cart that is driving past and then exit without hurting themselves. Or maybe they have to pick a lock on a house and traverse through an apartment avoid being seen.
With each of those scenarios, consider what failure might do to the scenario. I would avoid absolute failure and use some kind of "failing forwards": for example, if someone sees you, they aren't immediately caught, but rather someone alerts the guard, and while your group is able to hide in the shadows as they run past, now the guard is on the alert and escaping the city will be more dangerous. Or if you fail to climb the wall, you make it over but maybe someone injures themselves falling off the wall while scaling over, damaging themselves or a useful item. However you do it, make sure that you give them complications but not things that completely destroy the mission... unless you feel the need to do that.
