We played a one-off with this quest. One of the group was new to the overlord role.
Heroes: Andira the Bard w/ Aria of War and Shield of Light
Challara the Hexer w/ Internal Rot and Sunburst
Tatianna the Treasure Hunter w/ Dungeoneer
Raynhart (Can't remember the spelling) the Marshall w/ Zealous Fire and Shockwave, and Mace of Aver
OL had Basic I with 2x Dark Fortitude and 1x Blood Rage
OL picked Volcrux Reavers as the invading force, and Bandits as the support group.
In retrospect, reavers were a reasonable pick- deadly enough to damage the heroes badly if they got bogged down. Bandits were not optimal I think- especially with Challara in play putting out up to three attacks a turn.
I'll sum it up quickly- partially because we didn't finish and partially because my keyboard is messed up. Challara and Tatianna held down the gatehouse. (The OL often overlooked Brightblaze- that thing is surprisingly quick.) It took a while before we closed the main door in the waterfall. Tatianna wasn't often plagued by poison, surprisingly. Because the OL was still learning, as I've often seen with fresh OLs, they tend to pay little attention to their cards and be more engaged with the board. We didn't actually have a hero die- the warrior came very close. Andira's ability was very effective at keeping the cave spiders and low-health goblins and volcrux reavers at bay, especially since they would be worn down by the time they reached the exit, where Andira and the warrior were mostly camped.
We called it with three rounds remaining. The OL had scored 3 points, which I thought wasn't bad since the guy was green to the OL role, and with those monster choices Andira nearly carried the team in places. It was a lot of fun- our first real descent game in months.