I wouldn't say Friday night is a must, Saturday night is generally the big night out. Fridays tend to start out a little slow as people get into town and then pick up later. Sunday nights aren't too bad (there's Sunday afternoon tea), but not anything like a Saturday.

The trouble for you is traveling in on a Friday evening. The traffic from NYC will be very, very heavy. As I'm sure you know, if you don't hit a tunnel or bridge by 1:00p on summer Fridays, it can be a long wait. Once out of the city, you have two choices. You can take the NJ turnpike towards Wilmington, but the roadway merge at Exit 8A can be a lengthy delay and there's construction slowing things down around Exit 4, I think. The other option is the GSP south along the Jersey Shore to Cape May, where you can take the ferry across the bay to Lewes, just a few miles from RB. This is a shorter route, but the GSP is delay-prone as well and you have to time your arrival in Cape May to catch the ferry. We find either route takes about the same amount of time. Sometimes we'll take the ferry on a nice day, but generally we stick to the Turnpike.

For what it's worth, you'll generally find Sunday evening traffic going back much better than Friday traffic going down. If you're willing to wait 'til 6:00p or so to leave RB, it's usually not too bad. Leaving from 2:00p - 5:00p can be a bit ugly, though. Of course, the nicer the day the longer people will stay at the beach, so you might adjust your departure on the weather.

If you can do it, we've found the absolute best way is leaving the city Thursday evening around 7:00p and returning Monday morning about 6:00a. Makes for a looong Monday, but it's worth it to stay an extra night and miss the traffic.

That's a lot of info about traffic, sorry! But we do this drive *every* weekend in the summer; I think I can do it with my eyes closed!