How to complete both quests "Rescue Garren's child from Firkraag" AND "Retrieving the deed for the Windspear hills" and get 80K XP for each party member + 86K shared XPhttp://www.sorcerers.net/Games/BG2/Walkthrough/wspear.php#dun301
There are two ways to resolve the Garren and Firkraag confrontation (before you even fight against Firkraag). You can either rescue the child, or retrieve the deed for Windspear Hills from Garren for Firkraag. For each task, you get 40k XP for EACH PARTY MEMBER. Normally, you can complete only one, because if you accept the quest for Firkraag, the child dies.
However, there is a way to complete both quests and get both rewards.
1) Steal the deed from Garren
2) Enter the Firkraag lair, get close enough to Charm the Mage there. Once charmed, move him to your party. Steal the prison key from him. Do not talk to Firkraag.
3) Go back to level 2, rescue the child, get 22k XP
4) Go back to Firkraag. Tell him you need to rescue the child, then offer to get the deed for him
5) Talk to him again, give him the deed, get 40k XP each party member
6) Go to Garren and his rescued child, get 40k XP each party member
7) Go kill Firkraag once you feel like it, get 64K XP