I am currently running a game where the current plot line has the players attempting to reach Orv to rescue an ally. They are currently traveling through the Candlestone caverns, heading for the Court of Ether and the miles long drop beneath it to the Midnight Mountains. They will all be using rings of feather falling to make the drop, by my math it will take them 8 minutes to land in the mountain peaks below, so I am tasked with running 80 rounds of combat (we're all planning on taking an entire Saturday to do this in one shot). I'm not a complete sadist, so I don't actually plan on having 80 straight rounds of combat, and am assuming that they will possibly look for a cave midway down to break and possibly rest.
The party has a half-orc gunslinger, a human conjurer, an asimar cleric of Desna, and a tiefling rogue, they should all be 11th or 12th level by this point. There will be plenty of buffs to go around, and both casters have extend spell. In addition, 20 point buy, and close to double wealth for their level (as a reward for me beating the tar out of them on a regular basis, I killed the gunslinger twice last session...OK, maybe I am a bit of a sadist...;)).
Basically, I'm just wondering, mechanically, how to handle the combat, and especially movement. Under the effects of feather fall they'll be dropping at a steady 60ft/round, but how to handle lateral movement? Also bears mentioning that I do not intend for this to be particularly deadly, more cinematic and fun. So, all that being said, any advice on the best way to run this while keeping it fun, but still somewhat risky, would be appreciated.
With feather fall alone I would assume that they can't control their horizontal movement. If they have fly, glide (especially glide considering it's basically feather fall plus horizontal movement), dimension door, or anything that would allow for movement then sure, but with just feather fall I'd say they're going straight down.
Of course that's not to say flying enemies can't do things like Bull Rush them to adjust their positions a bit.
I don't know your PCs of course, but it sounds like they're all playing characters capable of ranged combat, so fighting in free fall shouldn't be too tough for them I think.
You could argue that characters in free fall would suffer the same weapon destabilization effects that levitating wizards are subject to. If you wanted to. You could treat lateral movement the same way too.
If I were one of your players, I'd probably just take the ring off, jump over the edge, and then free-fall at 200 mph until I got close to the ground and put the ring back on.
You could also just house rule it a bit for the sake of an interesting fight. E.g. Here's what my rules would be.
By default you fall straight down. As a move action you can glide half your move speed forward, or turn 45 degrees left or right (kind of like having a glide speed.)
Any melee attack basicly gives you momentum in the opposite direction. Thus, if your fling towards something and hit it head on, it cancels out your forward momentum and your not laterally moving any more. If you melee attack something with no momentum, you go flying backwards instead. If you attack something to your left, you go flying to your right. etc. etc.
I'd have to think about how you'd react to getting attacked. A full move action might allow you to turn more than 45 degrees in my mind, so someone sent flying away from the action could return in a round or two.
Also, I'd probably play this sort of combat on a hex grid.