I took this passage as describing his actions as a gossip. He wanted to hang around in order to get the latest scoop, knowing he had a ready audience in Mrs. Jennings for whatever he heard, saw, etc. Now that you mention it, though, I see that he had the added incentive (or perhaps merely a bonus) in being able to render service for which he would get paid as well.

It's a twofer for Mr. Delaford, oh happy man!