Actually,(I think) random deck plans are silly... You SHOULD know what the inside of a (Human Civ)ship is going to look like...
Doing random damage to the inside OTOH...
Well no, you should know what the bridge looks like but as they're armed with all different weapons and shields and so forth why would a "scout" have the same layout as if the hulls were flat out mass produced (and aren't things you mass produce both common and cheap? The more expensive ones would have all the more reason to not look the same.)
As for pulling it of how do you do the caves? Is it just squares with random lines connecting them? If that's the case for a ship it would probably be easier to start with the max area open, stamp down the bridge room at the front and then draw in the walls instead so all the rooms were right next to each other and then chop doorways out to re-connect them. If you were feeling trixy you might get it to produce a narrow corridor linking most of the rooms on larger ships.
You could also stamp down the engine room since it's pretty much gotta be near the back and then play connect them. Genning one side and then flipping it for the other side is also a consideration.
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Maneaters are the first consideration for plants but you could also have a variety that move a fair deal- earth plants are only mostly restricted in movement because the cell walls are rigid to give them internal water pressure but if the atmosphere was dense that might not be an issue and then there's always the option of plants using other fluids- perhaps on worlds with lots of acid there could be plants that spit at you (or ones elsewhere that spit seeds at you for a different sort of alien parasite.)
(Having young plants unfurl from most of the creatures you kill on a particular world might also be cool.)
And you could have a special world where the plants were converting the water into acid thanks to some irresponsible merchant transporting them to the world and you've got to remove them for the locals.
And if you look around your scifi you'll find ideas like very large plants with hollow interiors that could act as a cave system (or if you wanted to reference the book I have in mind you could have a rather dead planet with an abundance of flora within the plant.)
As for types of plants on earth the progression goes something like seaweed-> moss-> ferns -> seed-plants-> flowering plants. Lichens are a moss+fungus symbiosis but as we can all imagine giant mushrooms you've got another option (variation among mushrooms includes the familiar cap shape, cup shape, and something more like bread fungus where it grows structures shapes sort of like a light post,) and this brings up the option of plant-animal symbiosis creatures (if this were more hard scifi I'd say when the plants didn't need water pressure but since it's not no need.)
And if you want to think Wizard of Oz there are plants that could mess with the crew odor style. It's probably too much of a stretch to have them make you use oxygen faster since you're in suits but if you've done any more advanced speed handling slowing the crew down (or rarely speeding them up,) is an obvious option.
And lastly with a good science officer around perhaps you could heal injured members with certain plants (more likely at the expense of the plant.)