If you have been stumped while developing your own setting, you could do far worse than to model some of your homebrew setting mythology on the classics. There's a pretty good primer available on Greek and Roman mythology online at the Mythology Guide. Certainly, you could just grab stuff wholesale or even file off the serial numbers by changing the names around a bit, but I would suggest reading through them and making some notes on whatever inspires you and using those notes as the basis for something even more your own.
As a Harryhausen fan, you know I love the tale of Jason and the Argonauts. With not a lot of effort, one could take just the tale regard The Golden Fleece and turn it not only into the basis for an adventure but also to flesh out the locations as potential static encounters or ports of call for many gaming sessions. Remember, for a truly dynamic setting, you can't just build a few encounters and funnel the game toward them. What you really want to do to foster awe in your players is to have many places of wonder dotted around the map with some of the more likely destinations detailed more fully right away. Then as you learn what hooks seem to be interesting your players, and it's fine to ask them more directly, fill in the less detailed locations based on what they tell you they would like to explore in the near future. It's okay to wing it, to, to finish out an evening of gaming. Just be sure that you spend some time between sessions really putting some polish on the most favored places so that the players never feel as if they are going beyond the borders of whatever map you present. Players know, or should know, that a GM can't do everything at once. They will be happy working with you provided you show them that the wating is worthwhile.