Lower tire pressure - make sure you have a way to put air back in once you're on the road. You may need to get to 12 or 15 PSI.
Lower tire pressure BEFORE you get stuck.
Don't get too close to the water - eg don't want to get stuck and have tide come on over vehicle/trailer.
Bring plenty of wood blocks and shovel(s).
Do you have a winch on the TV?
You should have a recovery strap and a place to attach on the front and rear of the vehicle.
I would say get out on those beaches a few time without the trailer. You don't want your first beach driving experience to be with a large trailer behind you.
Go with a group if you can - so you can help each other if one gets stuck.
Make sure you have the phone number (and pricing) of someone who can help you out if you get stuck.
If you get stuck - don't spin your wheels and dig in further. It's much harder to dig/pull out someone who's dug in so deep that they're sitting on the axles and frame vs the wheels....
I don't know how ST trailer tires respond to running with low pressure, but you'll probably need to lower the TT tire pressure quite a bit as well.
Also, make sure you have some means to monitor transmission temps. The transmission will think it's pulling big hills the whole time....