Scenarios are designed to be about 4 to 5 hours in a go. You go in, do them and get out. Some are very combat orientated and others are a mix of mission tasks (which can be knowledge, diplomacy(intimated/bluff) checks, and so on), and a very rare few are very social orientated.
There are typically between four and six encounters in a scenario.
First Steps are a mix of the three styles.
-In Service to the Lore is a 'social/quest' event within Absalon, with combat
-To Delve the Dungeon Deep is your classic dungeon crawl, looking for trade agreements and a treaty weapon in a recently found siege castle
-A Vision of Betrayal is a cross country trek.
Modules fall into 2 categories.
-'Free Game Day Modules' are the freebies you can get off the site, and give you 1 xp and 1 prestige point. (No faction misisons) because they tend to be short and quick (I've done We Be Goblins! in like.. 4 hours, would have been less but we were all laughing)
-Modules: Award 3 XP (A level) and 4 PP because they are longer and more involved.
Some scenarios are really fun. Rise of the Goblin Guild was lots of fun, creepy singing pyromaniac goblins in a sewer complex. Others have a 'mystery element to them. (Murder on the Throaty Mermaid and The God's Market Gamble). Others pit you against the Societies rivals the Aspis Consortium (Before the Dawn Pts 1 &2, Severing Ties (of particular note since the mission is to RUIN issues between the consortium and an ally rather than outright killing everything in sight))