Heading down to PINS in the middle of March to do some camping and fishing. What can I expect to catch in the surf that time of year?

I really wish someone would answer this question, I want to know too.

pomps, whiting, croaker, sand trout, hardheads, sharks, reds, and others

LL makes a good list. Pretty much in order of probable catches as well . Might want to add black drum to the list. We'd suggest that reds could be second, third, or fourth on possible catches.
Dirty rough water will find lots of hardheads,possibly both drums, and stingrays. Cleaner water will give you a better chance at everything else on the list.
Depends on how warm and how rough the surf is when you're down there

I think in the middle of March, you are most likely to catch college kids on spring break!

That was funny!