I’ve never tried to set up a camp in another biome. Since you’d need to get everything there, including oxygen, it seems like a real hassle. I just live with the fact that at some point the “Long Commutes” message is going to have a permanent place on my screen until I can afford transit tubes.
You can prepare a little for entering slime biomes. You can start giving your guys vitamin chews early on. You can first tunnel into a nearby hot biome with balm lilies and grab some to make medical packs that will cure slimeling. Though slimelung seems just to be an annoyance and not deadly, so you don’t really need to do either of these.
I usually try to find a chlorine pocket above where I want to enter the swamp. I’ll dig out a pit just inside the airlock to the swamp area and then dig up to the chlorine so that it fall into the pit. I put storage containers in the pit. The chlorine will kill any germs off things put in the containers. This is where I store everything I put from the swamp biome until it is germ free. I also put a bottle emptier above the pit and drop in just enough water to cover the base of the storage containers and prevent slime from outgassing.
I have been exploring all the adjacent biomes without atmos suits. My guys don’t seem to mind short stints in temps up to 50C. Now that I found an oil biome, which is >70C, I’m starting to craft some atmos suits and an O2 supply for them (or I was until Rebel Galaxy Outlaw put a complete stop to my colony’s progress).