What does "An adventure for players levels 1-3" mean? I see this on the front of module books. Does this mean the players should begin the adventure between levels 1 and 3, with no hint as to what level the players will end up as at the end of the adventure? Or does it mean that players begin at 1 and end at 3?
I think you'll want to go with the Chaos Scar series. This is a DDI set of adventures for low level characters that should get you through levels 1-5. It's not a campaign per se, more of a sandbox, but should be no problem to string together if you're an experienced DM. I ran some of it with my newbie group, before that group ended, I had planned to run all of it.
I started with the D&D Encounters Keep on the Borderlands adventure; however, the adventure as written is just combat encounter after combat encounter, so I stretched it out and chopped it up a bit. You may have to find it on ebay if you want a print copy, I ran mine from a PDF.
Interspersed in that adventure I ran other side adventures from the Chaos Scar series, of which there are 15 for levels 1-4, which you can find here (DDI Subscription Required): Chaos Scar
1A Stick in the Mud 1B Den of the Slave-Takers 1C The Brothers Gray 1D Death in the Pincers 1E The Tainted Spiral 1F The Lost Library 1G A Chance Encounter 1H Eyes in the Forest 1I Elves of the Valley 2A Sliver's Call 2B The Shrine of Glass-Spire Forest 2C Dead by Dawn 2D The Hammer Falls 3A The Crawling Fane 3B The Splintered Spring 4A Glowstone Caverns
The characters were based out of Restwell Keep, which is detailed here (DDI Subscription Required)
The map of the Chaos Scar is great and can be found here (Free, as a .jpg)
I really liked the background of all the adventures that I ran and those that I read. I was hoping to use more of them but we stopped after 2 levels unfortunately. If I ever run another newb group I would probably use this series again.
After what's listed in the first link there are the following adventures:
LVL Dungeon# Name - 4 178 The Crawling Fane Chaos Scar - 4 180 The Pillar Of Eyes Chaos Scar - 4 182 Vanguard Tower Chaos Scar - 5 181 The Slaver's Stone Chaos Scar - 5-7 192 Scarred for Life Chaos Scar - 6 183 The Radiant Morn Chaos Scar - 6-8 193 Rumble in the Valley Chaos Scar - 7 184 Head in the Clouds Chaos Scar - 7 196 Reflections of Ruin Chaos Scar - 7-9 189 Scarblade Chaos Scar - 8-10 186 The Runecutter's Ruin Chaos Scar - 8-10 190 Pit of Delirium Chaos Scar - 8-10 197 Heart of the Scar Chaos Scar
I hope this helps!
How should I go about choosing an adventure for a group of new players?
The most important thing is to find something that speaks to you. If the premise leaves you flat, you are not so likely to be able to breathe life into the campaign.
The other most important thing is to find something your players will enjoy. Heck, they'll probably enjoy anything you DM cuz you'll be so great, but if they are all obsessed with dragons, maybe the module with the dragons, right?
What qualities should I look for?
Make sure the module you select is for new first level characters. (Unless you really want to start at a higher level, which would make your work a bit harder.)
Modules labeled introductory are good for starting DM's and players. They often reprise the rules you will need to be familiar with, and give points to where to look rules, etc.
CAVEAT: The word "introductory" doesn't have a fixed definition. Some introductory modules will be entirely self-contained, while others might require other materials, such as the Monster Manual and the DM Guide.
A module might be (A) specifically for particular game rules (like D&D 5e), (B) be "compatible" with a set of game rules, or (C) it might be just the "story" part without the monster stats. A module of the first type will be easiest to use.
...and how can I tell if a published adventure has them?
I think that a trip to your Friendly Neighborhood Game Store might serve you well. The staff of typically pretty knowledgeable, and you can flip through the merchandise. Other customers often might offer their insights as well.
This site and others have chat forums where you can get suggestions and discuss.
You might also read product reviews online. For the in-depth info you are interested in, I'd favor review website like Escapist Magazine over reviews at online stores (although both have their place).
Should I restrict myself to official WotC adventures on the presumption that they have the best writing and playtesting or is there a way to identify third-party adventures with a similar (or higher) level of polish and quality?
Probably not a bad idea to favor the WotC's D&D 5E material, if that's what you're going to be playing. This has more to do with the encounters being tailor-made for 5E, than one company's material being better than another.
So which are those?
Applying my own answers to your criteria, The Lost Mine of Phandelver in the D&D Starter Kit, and Tyranny of Dragons both would be solid choices. Phandelver also would be a good fit for the number of play sessions you mention.
Tyranny of Dragons is an updated version of the early D&D 5e releases: Horde of the Dragon Queen and its sequel, Rise of Tiamat. Its updates include play balance fixes, perhaps most notably in earliest set of encounters, which make this module more appropriate for beginning DM’s and players.
NOTE: More recently, another official introductory module has been released: Dragon of Icespire Peak. I haven’t read through this one yet, so I cannot comment on its specifics.
You'd mentioned social encounters...
Most D&D modules have a whole lot of fighting involved, and the two I mentioned are no exceptions. Without doing any spoilers, Phandelver probably is more dense with opportunity for social encounters than Horde of the Dragon Queen.
The existence of opportunities for social encounters, of course, has a lot to do with your DM'ing. Monsters don't have to attack the party on sight, even if the module says they do.