I see Chris wearing one of these:
Odds are he'd go with his electronics and whatnot, then sit on the beach. He might walk around and wade a little, but with all of his stuff in his hands because (rightfully so) he wouldn't trust anyone not to take them. He might go back and store his stuff in his car, then go try to swim. He might take advantage of the "no arranged seating" thing and put a towel near a girl he thinks is cute.
He might ask someone to put sunblock on him or ask if they need reapplication. He'd creep people out in general, although I think that one or two girls might be kind enough to put sunblock on him. He'd then try to engage them in conversation, as he'd think that applying sunblock on his back leads directly to them applying china to his duck. Many would outright ignore him or get up and try to leave. Chris might follow them. Ultimately he'd have someone confront him, saying that they don't want him around. It might take a while, as Chris spends most of his time waiting for others to approach him. In the end he'd get into a fight with someone (girl, guy, lifeguard, police, etc) who would tell him to take a hike.
The nearly naked men might put him off, but it would be slightly balanced by all of the girls in their swimsuits. I think he'd maybe make it through an hour a day max, as he'd probably keep repositioning himself to where he'd only see the girls.
Actually... Chris has already done this. It was during the BlueSpike saga, when Chris drove out to another state to find Julie. He ended up talking to some black woman who was at the address, who said she didn't know any Julie. He drove out there and back with little trouble. He didn't bother telling Borb where he was going and they were pretty pissed. They ended up filing a missing person's report and everything.
So odds are that if he did this again, it'd probably end up being something along the same lines. Barb would freak and file a MPR, only for Chris to stroll back into the house a day later.
http://sonichu.com/cwcki/Ohio_trip
(You know, if the other posts aren't blatant enough.)