Lewes doesn't try very hard to be a beach town, which is exactly why people who've done the other Delaware beaches end up loving it most. The historic district runs on foot traffic and porch light, not boardwalk noise. The beach itself — calm, bay-facing, more Sound than Atlantic — is almost beside the point.
What Lewes actually offers is a whole day that doesn't require sand at all: a bike ride down to Cape Henlopen, a wander through Zwaanendael's brick streets, an afternoon watching the ferry come in from Cape May loaded with cars and bikes and sunburned families. It's the only Delaware beach town where the ferry terminal counts as a legitimate afternoon activity.
Go to the fishing pier at the end of Cape Henlopen Drive right as the evening ferry comes in — you'll have the view of the harbor mouth mostly to yourself while everyone else is still parking downtown.