Mysterious Letter

It reads:

We have been told you are honorable adventurers and we would take avail of your services. A small band of hobgoblins have taken refuge in a cavern a number of days to the northeast. If you are to eradicate them, we will pay you the princely sum of twenty-five gold pieces. Directions: follow the road to Garios. A few days before you would reach that city, you will come across a ford in the river where lightning has hit a tree. Follow the arrows into the woods, they will lead you to said cavern.