So We'll Go No More a Roving
The speaker has decided to call it a day, with his partying and wandering around at night, that is. He still sort of wants to be out there, having a great time, and darn, that moon is still beckoning to him. At some point, though, it gets old. Gotta grow up sometime, ya know? It's kind of like getting new shoes when you're young; your feet get bigger, and it's time to get new ones. Same idea here, only instead of new shoes, it's new ways to spend one's time ("older" ways).