"And you were all so damn worried about what might happen and now we've wasted food and drink. Fine, let's just keep going and see if there's any actual supplies along the way or if we're gonna starve or die of thirst. I know for certain I'm not trusting the yellow rain or whatever this is."
Collect some of the yellow rain in an empty container and try to determine what it is/does. Without drinking it myself - offer it around to other people if they wanna try it.
Also determine whether it's flammable.
You collect some of the rain. It doesn't really smell like much, but it feels and looks oily.
You try lighting a bit of it and it burns weakly.
Keep an eye out for any of those pesky ghosts.
You see no bone thieves around for the moment.
"It wasn't a waste. I doubt any of us ate since we left the hotel yesterday."
Look around for landmarks. Like a hotel.
Well, beyond the largest boulder you can see or the mountain range you're heading into, there's not a whole lot visible right now.
If piecewise was very evil, he would have the fog turn into a cloud of gasoline, since Comrade touched it while passing through... Unless it's made out of some strange liquid not affected by his powers of transmutation or it's not dense enough for the effect to spread.
((I do not think this fog is made of liquid particles, it is more of a border between realms made of inconceivable substance. Sort of. I think. And given my powers were nerfed to unstable, this could end real bad.))
If there is a road ahead, drive along. If there is no road, try to find some dry place where the party and the jeep can fit in.
The road leads across the steppe and up into the foothills of the mountains. The foothills are great piles of cracked black stone, thinly coated in scraggly grass. There are things living here, among the scattered stones and in the small crags and hollows. They look birdlike with gray skin and wide, staring black eyes. Their bodies are almost monkey-like, but with 6 long, thin, primate arms and no legs. They skitter and hide whenever the jeep drives passed, but if you look in the rear view mirror, you can see them pop back up like prairie dogs and watch you go. The soft rolling boulder-pile hills eventually lead up into the jagged obsidian mountains. The road narrows and becomes increasingly treacherous, trace the ridges and valley edges. The valleys and the mountains seem strange. The mountains are each a singular thing, surrounded by massively deep and sheer valleys, like icebergs floating in a shadowy sea. You think you might see things down there, in those Stygian valleys, geometric shapes which might belie man made structures. But getting down there would be difficult.
The road eventually leads to a large, badly rusted and quite old looking metal bridge that spans the gap between two mountains, connecting the road up to where it continues on into the clouds. As you look ahead, at the mountains, you realize that it's not that the mountain peaks are vanishing into the clouds, rather that the mountains end in abrupt plateaus at the cloud line.