Since a single quest can take some time, I wanted to post a record of all the possible avenues that the characters can take to complete this epic. I'm only posting the ideas that are known by the characters through their adventures. These are story seeds I planted when we played this as a tabletop up to now.
Oytwood Main Story Arc:
Taking the Olvewater Trade Bridge: Currently held by giants and their allies (orcs and ogres)
Taking the Oyt River Trade Bridge: Currently held by giants and their allies (orcs and trolls)
Raids on the Oytwood Trade Road: This road heads from Preston north to Midwood. The giants have recently been using it to ferry supplies and troops. Disrupting that supply line is a priority to isolate Preston and troops holding the bridges.
Raid on Preston: Breaking the giants' hold on this city should weaken the giants' strength in the Oytwood and open up supply lines for a larger force. Taking Preston is also personal for Martin as well as being a victory for the Knights of the Watch and Dispatch.
Build an alliance with the wood elf cities and/or tribes within the Oytwood:
Lynlai (city): party is building a reputation with the city, and it seems to be amenable to an alliance.
Oytlove (city): party has two allies from Oytlove (Kessa and Laudyn) who they aided when attacking the orcs that were kidnapping elven children. Other than those two, the city is rumored to be adamant about its isolationism.
Nulai/Fort Hopemeet: Little is known about the fort or the city, although the Lupinals were originally heading there to work with the High Druid Hale.
Starfire Tribe: Lady Glassblower mentioned this tribe as a potential ally in the northeast section of the Oytwood. Justice done on Nerraune could bring the clan to the negotiating table.
Build an alliance with the woodsmen of the Oytwood:
Recruiting or conscripting humans within the forest. They are scattered and do not have solid organization.
These quests are simply other options for adventure (and experience) or other alternatives to waging war against the giants.
The Dark Fey: The forest is apparently rebelling against all forces involved in the conflict as groups of evil fey have been assailing the people of the forest. There attack seemed to be centered around a sacred grove of another druid lord.
When are there not? These bandits have taken complete advantage of the war to prey on everyone. It is also known that some bandits allied with the orc forces remaining in the Oytwood after Gione was removed. It is unknown how organized these forces are.
An Alliance with Orcs:
Gione "Elfslayer" impressed by the characters' attack on his position exchanged the elven children for his life and his remaining forces. He mentioned meeting him at a fort 30 miles south of the Lea in Geoff proper. It seems that mad orc sorcerers and drow have displaced the ruling council to which Gione has sworn his loyalty. Gione does not wish to be beholden to mad orcs and drow. The party has until the end of Coldeven to have this meeting. Of course, an alliance with orcs could damage alliances with other races.
The Savior of the Oytwood:
Some human warrior is claiming to be able to chase the giants out of the Oytwood if all within the forest will swear fealty to him. He has been rumored to be impressing, quite forcefully, people into his army.
Ruins of Lutrell Lake (Personal for Arlie):
Lutrell Lake, second home for Arlie and former home of the late Fawn, was destroyed by troops sent by Gione. However, when elves and woodsmen from Lynlai went to investigate and rebuild they were chased away by undead. How the undead got there is unknown. Nerran, elven wizard in Lynlai, sent this information to Forlin by way of a sending.
The Dragon of Derelion (Personal for Arlie):
The emergence of Shadow Dragon during the battle for Derelion in the Dim Forest turned the tide of battle against the alliance of elves and men against the giant army squarely to the side of the dragon and creatures from the Plane of Shadow. Investigating Derelion's fate, the Dragon, and the Plane of Shadow's influence is personal for Arlie and politically advantageous if successful.
The Stubbornness of Dwarves (personal for Hlin):
The clans of dwarves in the Barrier Peaks are in heated clan disputes and has led to them being unable to aid Geoff. Returning to resolve this conflict could help bolster the liberation of Geoff with another army.
Staunch, but Short, Allies:
The gnomes and halflings of the Stark Mounds have regrouped and are moving within their own lands. They even made a small expedition to Lynlai as the party was leaving (Hlin traveled with them). They are based somewhere south of Gorna, but are not ready to move. Outside of the Oytwood they could be helpful allies if a southern assault on giant-held lands is preferred.
Contacting the Druid Lords (was possibly important to Fawn):
Five Druid Lords live in the Oytwood, pursuing their own interests, but only one has involved himself in the war, Hale. Nerraune is obviously no help at all and is probably better if removed. Another high druid is rumored to be behind the evil fey. A fourth wanders the Oytwood killing giants with a pack of dire wolves, but is otherwise uninterested and violently opposed to talking. The last, the Archdruid Alonquinn, probably the most powerful force in the Oytwood, observes but has never engaged. His sacred grove is actually beneath the waters of the Oytwood Confluence. These would powerful allies, although quite difficult to obtain.
I will update these as new ideas and hooks pop up. Let me know if I missed any.