NO SPOILERS
Conquest of Bloodsworn Vale was the first Paizo wilderness-themed adventure in its GameMastery series of modules using the D&D 3.5 rules. As the title indicates, the adventure takes place in Bloodsworn Vale: a largely "untamed" wilderness claimed by Korvosa. I know some GMs integrate it into a run of
Curse of the Crimson Throne, but I ran it as part of my "Roots of Golarion" campaign that ties together scattered pre-Pathfinder RPG adventures. Anyway, the long and short of it is that
Conquest of Bloodsworn Vale was a blast and proved the favourite of everyone at the table. The structure of the module encourages a lot of free-form exploration and influence over the setting, but with a larger overall story so it's not a 100% sandbox. It's a style of adventure that was popular in the early days of D&D but that we don't see so much in an era of heavy railroading. I definitely recommend this one, especially if your players have gotten tired of dungeon crawls or feeling like they're just acting out the plot points in a novel someone else wrote.
SPOILERS
The premise of the module is pretty straightforward: King Arabasti II of Korvosa has decided to exploit the potential of Bloodsworn Vale by establishing a trade route through it. He's charged a trusted knight, Sir Tolgrith, with oversight of a permanent encampment called Fort Thorn and a single goal: get a road built. As the adventure begins, Fort Thorn has been built and about half of the road has been constructed, but recently, construction has been delayed due to various problems. With the king expecting the road to be finished in sixty days, Sir Tolgrith has decided to advertise for adventurers to help deal with some of the obstacles his work crews have faced. The PCs' adventure hook is the oldest around: solve problem, get rewarded.
The issue Sir Tolgrith needs immediately help with is the mysterious murder of an entire work crew and its guards. Searchers later found the bodies, and all were missing their ears and pierced with dozens of small arrows. Assuming the PCs take up the mission, they'll find the site of the attack and could find a couple of different clues leading them to the culprits: a group of evil fey, created for this module, called roseblood sprites. There's a full write-up of these fey in an appendix, and I think they're really well done, with their special abilities matching their flavour and lore in a smart package. The roseblood sprites reside in a glade and live partially underground, and, to meet with their Rose King, the PCs will have to deal with animated trees, giant bees, poison, and more. These roseblood sprites are vicious little fey, happy to feast on human flesh. They've been attacking the work crews to collect ears as tribute to the evil wizard on the far side of the valley who has threatened to burn down the glade (more on him later). It all serves as a grisly, but memorable series of opening encounters, and gets the module off to a strong start.
After dealing with the Rose King, the adventure really opens up. Sir Tolgrith has a small laundry list of problems he needs help with: a pack of owlbears living south of Fort Thorn, large spiders that have dragged a member of a work crew away, bugbears that make constant hit-and-run attacks to stymie construction of the road, a lake that mysteriously turns putrid but only for a single day each month, and more. The PCs are also encouraged to serve as surveyors and locate a few different types of valuable resources that can be mined or harvested, and if they're successful, Fort Thorn begins to thrive and offers more goods and services for sale. Later on, the PCs may need to negotiate with lizardfolk who feel threatened by Fort Thorn and, if diplomacy isn't successful, enjoy a mass combat against almost 100 enemies!
The GM is given a timeline of events that starts with the PCs arrival on Day 1 and ends with King Arabasti II's emissary arriving on Day 60 to inspect the progress of the road (ending the adventure). Although certain events trigger on particular days, for the most part the PCs are left to their devices to deal with various problems, get to know Fort Thorn, and explore the valley as they see fit. Bloodsworn Vale is a big place, so there's lots of opportunity for wilderness encounters in the days spent away from Fort Thorn. It all builds to classic, free-form emergent gameplay, where different groups may experience the adventure in very different ways. Some may really take to the openness of the valley and decide to build a stronghold, others will be very devoted in seeking out every threat to Fort Thorn to make sure that road gets built on time, others will just wander around and see where each day takes them, etc. My group, for example, loved exploring with the goal of finding particular natural resources, but also spent a couple of days of "vacation" at the lake (after clearing it of the undead responsible for its periodic putridness!). Feeling free to go about things their own way and tackle what they want when they want can really empower players to connect to a setting.
As I said, it's not a complete sandbox, however. The adventure formally ends after sixty days, and the PCs' are judged according to "accomplishment points" for doing different things. The more accomplishment points they have, the more progress is made on the road and the more (or less) rewards they'll receive from Sir Tolgrith at the end. This is not one of those modules that only plans for a happy ending--the PCs could get everything from a prison term for utter ineptitude to a knighthood for great success (and various things in between). I like it when success or failure isn't judged by a single thing (like winning a big battle at the end) but by the cumulative evaluation of what's happened throughout the adventure.
There is a major villain in Conquest of Bloodsworn Vale--an evil sorcerer named Lord Vardak. Vardak considers Bloodsworn Vale his domain and, several weeks into the adventure, begins sending flame drakes to raid Fort Thorn each day. (I hadn't realised flame drakes were created specifically for this adventure; they've proved a very useful addition to the game's bestiary.) Vardak threatens to destroy Fort Thorn utterly by unleashing the power of a (new) magic item called a seed of fire. If the PCs want to stop that from happening, they'll need to confront Vardak in his fortress. I thought this section of the adventure was fine, though Vardak is a pretty cliched villain and we're not offered any backstory or interesting distinguishing characteristics. Still, I guess it's good to offer a more traditional climactic sequence (even if it need not come exactly at the end of the module).
The back matter of the module consists of the excellent write-ups I mentioned for flame drakes and roseblood sprites. There's also a two-page description of Fort Thorn. I wish this had been longer because, apart from a hermit, the inhabitants of this camp are the only NPCs the PCs will have to interact with throughout the entire module. Sometimes even a little can go a long way (my group got very interested in the mention of thefts and uncovered the culprit), but more would still be better here. As for art, I think the cover's pretty cool; the interior art is a more mixed bag, though always serviceable. Maps are strong. The overall design of the module is great, with plenty of sidebars, charts, and "designer notes" (tips from the writer on how to handle particular things that might arise; I love these things, and wish Paizo hadn't dispensed with them).
Although it's now almost fifteen years old, Conquest of Bloodsworn Vale really holds up. Each group can make their own adventure, and there's plenty of room for the GM to insert new encounters and NPCs. It's also easy to see how the campaign can continue after the module is formally completed. I'd place this module at or near the top of the list of ones I've run, and definitely recommend it.