I don't think that I had ever heard of Daniel Rowlands before, but what a fascinating look into the world of the 1700's. First, I am always amazed how busy and bold some of those guys were. He went anywhere, preaching to anyone. He did it nonstop, all the while having a deep impact on young preachers:
From then, he also took invitations to preach in chapels or barns or the open air if necessary. He followed up by establishing of methodist societies around much of Wales. Upwards of one hundred ministers in this association regarded him as their spiritual father, a key part of Welsh revival.
Second, the world has always been wicked. There have always been serious problems in churches:
[M]any Welsh clergy were neglectful, or drunkards and gamblers.
Finally, God can use you to make a difference in a dark, unknown corner of the world. Here is how Ryle described Rowlands' ministry (emphasis mine):
Never, perhaps, did any preacher exalt Christ more than Rowlands did, and never did any preacher leave behind such deep and abiding marks in the isolated corner of the world where he laboured.