Details and pictures (click to embiggen!) after the break.
Fortunately, my friend and the (I think?) only other dude in our group already had a small stash of food and some equipment, enough that I wouldn't starve immediately or get left out in the cold for any random person to gank. So we have a little underground bunker, but it's not much to look at.
Amusingly, despite this being a PVP-oriented server, I'm basically back on architecture duty. I seem to be the most experienced builder in the group, so they put me in charge of making our home look like something other than a box of dirt. Which it was, until I built us a sweet observation tower and some walls. It's all very basic at this point (and plain-looking; exotic materials are quite rare at this point), but I think it's a good start.
Most importantly, it gives us an above-ground area safe from monsters and, for the most part, other players. Anyone clever enough COULD do some elaborate siege engine thing where they build really high on the edge of our territory (only members of our faction can build or dig within our borders) and then jump over and in, but that involves a lot of fall damage risk. I'll make this more secure later.
Plus, even if enemies breach the walls, they still can't get into the main base where our loot is. Non-faction members can't use doors, switches, trapdoors, etc. in our territory. Through some strange twist of server permissions, I can use doors just fine, but not trapdoors. The permissions gods are fickle and highly specific.
After giving our faction a little above-ground pizzazz, I tackled our other main issue: there's no damn trees on this server. Faction territories are pretty small, and wood's an important resource, so the world has been pretty much stripped bare of wood, and ranging out far enough to find natural trees is very risky. So, I built us an underground tree farm, safe from the ravages of the other jerkfaces on the server. Here it is during excavation:
And here's the final product:
We only have a few saplings, but those should multiply as we get a few harvests. I think I got enough light for the trees to grow, and the whole shebang is safely within our territory, so no one should be able to dig in and steal our trees. Not even the dreaded beavermole.