Does barkskin stack with stoneskin, ironskin, etc..?

If you're thinking damreduction - it doesn't have any.

At this risk of sounding completely inept, what is the difference between ac and damage reduction?

AC makes difference between "hit" and "miss" on melee strikes on low levels. It also matters for several skills and abilities like armor deflection, shield block and others.

Damage reduction straight up cuts the damage you receive. Like with 20% damage reduction (stone skin) you get 80 damage instead of 100 on a solid 100 damage hit.

Because those make your login visible to others. So now we know you really are newb (at least your handle is completely new).

Solid advice. Thank you. Any other tips for a newer player on playing a ranger? I noticed dex seems to trump strength these days, but rangers have a lot more options than they once did.

There is a ton of information. A lot of details and nuances.

Or maybe explorer if you feel like it - that will give you more tolerance towards non-home terrains. Don't bother with the fancy as your first ranger char, go with default. Treat it as a learning experience, don't be disparaged if you die, pick yourself up and try again.

General newbie ranger pointers:

1) Stay in the wilds. It is very important to be "at home" for many ranger skills, this is most noticeable with fastcamo, but matters across every skill. Don't even do the academy post the leather quest, finish it and leave for the wilds. Set your prompt accordingly.

2) Pay special attention to your terrain. It will be in caps and your skills also depend on being there. Some plain don't work in other terrains, some are reduced in effectiveness.

3) Rangers are for the patient - set a perfect trap and execute on it.

4) Waylay beats regular ambush 90% of the time because of the lack of lag since it can be followed by a bearcharge.

5) Join outlanders, this will keep you less bored than you'd be otherwise.

6) Bearcharge is size-based. If you have someone in a snare and want to kill them, quaff an enlarge, waylay and bearcharge. Sometimes it will work.

7) Magic is your friend. Talismans are useful in a wide variety of situations, explore IC.