First of all, read the DMG:88-9, which will answer many of your mechanical questions (including quicksand). Then read the water environment sections, as well.
Quasqueton said:
What environmental things make a swamp adventure different than say travelling through a normal forest, or boating on a lake?
Swamps are
wet. Even the high, "dry" ground usually isn't dry. The marshy ground is, at best, damp. Many places are covered in from a few inches to a few feet of water. Most of the water is barely moving. Basically, none of it is drinkable, due to micro-organisms.
Vegetation is common, but clumpy, and moss and creepers are hanging, dripping, from the branches, everywhere. Because of all this, firewood will be tough to find, and fires tougher to get lit... (I'd make a PC make a Survival DC:10, with a -2 Circumstance Penalty, unless they can tell me where they'd get dry tinder).
Quasqueton said:
My first thoughts are bugs - swarms of little vermin biting the skin, getting in the eyes, and spreading diseases. How can this be worked in game mechanics? Should their be distraction penalties?
Penalties and disease seem a bit much, to me. Just describing the swarms of insects, and waking up with the bites in the morning, seems like more than enough, to me.
Also, pine tar (among other things) can be used as a natural "insect repellant". The Druidic
Repel Insects works better.
Quasqueton said:
A minor Fort save each day to avoid a disease? How do swamp animals avoid this aggravation and danger? Maybe having a natural armor bonus (+1 or better) protects the swamp creatures?
Diseases can be rolled for (Filth Fever seems suitable), and simply being in the swamp counts as exposure, but I don't think the PCs will appreciate it. I'd save that for being bitten, and/or drinking unpurified water...
Most swamp mammals get bitten by insects. Most reptiles and amphibians avoid them by staying underwater. Yes, thick skin helps, but doesn't solve the problem.
Quasqueton said:
How to mechanically model the extreme humidity and moisture of a swamp? Some swamps are hot, some are cold, but all are wet. Is there something in the core rules that could "enforce" the problems with keeping things dry without having to create a new mechanic? If a new mechanic is needed, what should it be?
The easiest solution is just to warn the PCs that leather requires "waterproofing", and then supply "waterproofing solution" at a cheap price. This could be mink oil, or something alchemical. Then, for those who use it, no problem. For those who didn't, let the leather become encrusted, and begin to rot (unless enchanted).
Quasqueton said:
What other hazards and effects would adventurers find in a swamp, besides new monsters? Quicksand? How to work this mechanically into the environment?
Detecting unsafe terrain is a DC:15 Survival check. By about 10th level, Rangers (and possibly Barbarians, Druids, and Clerics of Travel) should have this down, pat.
Quasqueton said:
I want to have the PCs really *feel* they are in a swamp, but I don't want to just punish them to the point of making the adventure unfun. How can a swamp adventure be different than a forest adventure beyond the monsters encountered?
Movement, first and foremost. Whether afoot, or poling flat-bottomed rafts. Lots of slippery footing (DC:5 Balance checks, IIRC). Occasional swimming. If the PCs take horses with them, their hooves will swell and crack, from the water.
Trouble finding dry wood and drinkable water. See above.
Problems navigating. Paths will be confined to the high ground. "Ground" may disappear, at high tide.
Problems with finding places to camp. "Dry ground" isn't, and bedrolls will become wet, and then refuse to dry out. Ditto for clothing. Chafing and rashes will soon follow.
Lots of things in swamps tend to be nasty, and either cause disease, or have poison. Fritz Leiber, in his Nehwon novels, invented some nasty little footpadded "salt spiders" to inhabit the salt marshes outside Lankhmar... You should invent a few new nasties (including some plants) to inhabit your swamp.
Water also makes falling, dropping things, and/or being disarmed a problem... Losing a weapon takes on a whole new meaning when you have to search through muddy water to find it...
