Rehoboth and P-town are only similar in that they are both small towns. Where P-town is very gay, In Rehoboth if you don't know where to look you might think there's no gay life at all. Since the Renegade closed (and, by the way, it was really only a weekend place) you're left with the Blue Moon and a few other bars/restaurants.
The Blue Moon is on Baltimore Ave and is usually pretty packed on Fridays and Saturdays for happy hour and later. They also have a nice restaurant. Stop in there or at one of the more obviously gay businesses on Baltiimore Ave for "Letters From Camp Rehoboth" the guide to all the gay happenings in town.
The gay beach is Poodle Beach at the far south end of the Boardwalk. Literally at the point the Boardwalk ends. (About a 15 minute walk from the center of town) There's a more lesbian and somewhat gay-male beach on the far north side of town in the state park.
In August there's more of a gay crowd during the week than the rest of the year, but it is much more crowded on the weekends in summer than during the week.
It's a nice town and you should be able to find things to do. Hope this helps.
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