The Nightfall DnD Preparation Thread

Okay, so, if you want to be a scout, you will want to be stealthy, so hide and move silently, and good at spot, listen and perhaps search. For Swift Ambusher, you also want to be good at atleast tumble. You are obviously starting with a level as Rogue. That is definitely a good thing to start with, since it gives you a lot of skillpoints. However, you should consider taking some alternative class features. That is, features that allow you to replace one thing your class can do with something else. One example of that is obviously the Martial Rogue variant Mather is using, that loses the Sneak Attacks but gains the Fighter bonus feats. If you want to Sneak Attack a lot, you might want to consider using either Penetrating Strike or Death's Ruin, both trading away your Trapsense in order to be able to deal at least some sneak attack damage to some things normally immune to sneak attack damage. Please note that this makes you in no way worse at finding and disarming traps, it just makes you a little less protected against them if you FAIL to disarm them. Also note that, unless Mather decides to trade away his Trapsense as well, he could play the role of the trap remover guy in the group, if you were worried about getting hurt by traps you failed to disable. Note that it only helps when you are in melee, ranged attacks won't benefit from it, so if you want to focus on ranged attacks, you might decide to skip this option.

Scouts have some neat tricks you will gain by taking up to four levels in it, more is not really giving you anything if you want to be a swift ambusher.
Level 1: Trapfinding is obviously pointless to you, unless you decide to trade it away for something else. You also get to add 1d6 damage to all your attacks during any round in which you moved at least 10 ft. There are restrictions who can be affected by that damage but simply said, most things you can't sneak attack you also can't skirmish against. still, it's a neat bonus. Scouts also get 8 skill points, just like Rogues, which is very nice and you obviously get the +2 to Reflex saves, which makes your reflexes even better.
Level 2: You gain a +1 bonus on Fortitude Saves and on Initiative, as long as you are wearing Light or no armor. You gain Uncanny Dodge, if you don't have already, which gets upgraded to Improved Uncanny Dodge if you DO have it already, also, all levels in classes that grant you improved uncanny dodge stack for the level of the opposing rogue needed to sneak attack you. You could of course decide to trade one version away for an alternative class feature, Disruptive Attack is a really nice option for archery based Rogues to deal with some of their enemies. You also get +1 BAB and a +1 on Reflex saves.
Level 3: Fast Movement is nice, unless you can get something better, but still, never bad to have. Your Skirmish now gives you a bonus to your AC when you've moved, which helps you survive in melee, if you need to go into melee. Trackless Step is a really nice ability, which makes it harder for enemies to track you, perfect if you want to be sneaky for a longer time. You also get your normal +1 BAB and +1 to your weak saves. This is the minimum number of levels you HAVE to take in order to be allowed to take Swift Ambusher.
Level 4: You get a bonus feat, chosen from a small list, most of which are more or less crappy BUT Swift Ambusher is later added to that list, so if you take the fourth level in Scout you can use it to take that as a bonus, which is nice. You also get your normal +1 bonus to BAB and Reflex saves.
Level 5: You get Evasion, which Rogues get at level 2 and your Skirmish improves, which it also does if you take levels as Rogue, thanks to Swift Ambusher. You get no increase in BAB or any saves at this level, which is why you shouldn't take level 5.

So in other words, you should take either three or four levels as Scout.

I also want to say a couple things about the Swordsage. Since you have unusually good Wisdom for a Rogue, which gives you a nice bonus on Spot and Listen, fitting your role of a scout, Swordsage is an especially good choise to you.

Swordsages are one of the three "Martial Manuver" classes, classes from the Tome of Battle that can get special tricks and stances. These alone are usually reason enough to take some levels in one of them. One Stance gives you +2d6 bonus on Sneak Attacks, for example, which is very well liked for many Sneak Attack characters.

Level 1: A +1 bonus to Initiative (which stacks which the one you get from Scouts) and Weapon Focus with multiple weapons, depending on the Disciplin you chose. Sadly, the Shortbow can't be a weapon for that, though the Dagger can. You get a +2 on Both Reflex and Will saves, though you only get 6+Int skill points, so you'll get two less skill points, which is a bit of a bummer.
Level 2: This is the earliest where you could possibly get that stance that gives you +2d6 Sneak Attack damage. It also allows you to add your Wisdom Mod to your AC as long as you are wearing light armor, which is at least a nice +2 in your case. You get a +1 on BAB and on both Reflex and Wisdom saves.

Depending on when you take those two levels, it could also give you such abilities and short ranged teleportation and dealing ability damage to enemies, which can be great if your sneak attacks fail to hurt them.

Besides those you should probably mainly take levels as Rogue, though some PrCs might be worth considering.

The Nightsong Enforcer and Nightsong Infiltrator are both PrCs that are more or less easy to enter and that offer good teamwork benefits, either for, well, fighting or sneaking and infiltrating. Most people prefer the Enforcer, because they are easier to enter and, arguably, better, though noone would complain if you want to take some levels as the Infiltrator.

The Spymaster is more for a Spy kind of character, one who impersonates and stuff. I just thought I should meantion it just in case. Plus, it's one of the few PrCs where the number of levels is NOT dividable by five. Plus, I LOVE the capstone ability, Deep Cover is brilliant, though perhaps more so as an immensly evil tool for a GM then for a player.

Thief-Acrobat as well as things like the Exemplar or perhaps the Dungeon Delver are options if you especially want to focus on some of your skills, though I am not sure if they'd be the best options for you.

The Assassin is of course one of the classic and still surprisingly good options for a Rogue, but we already said, it'd be pretty OOC for Drea. Plus, you literally HAVE to be evil. There is a joke version that is the same as the Assassin but Non-chaotic instead of Evil, but not only was that released as an April Fools joke, it also wouldn't help you since you ARE chaotic.

Another classic is the Shadowdancer, which requires some shitty feats and some points in Perform (Dance) but if you do decide to go for it, it offers you an incredibly helpful ability, hide in plain sight, with the first level already. The second level would only be worth it if you for some reason traded Evasion away, else it is okay at best. After that it becomes kind of weird, since it gives you some summoning abilities, some illusions and even short ranged teleportation, though if you want that, I'd advice going for the Swordsage instead.