We stayed in a Gold caravan at Camber Sands. The caravans are all different types so you might not get the same layout every time, but in the one we stayed in, we did squeeze the travel cot into the second bedroom -- it fit in the floor space at the foot of the beds.
we're going in two weeks, but won't know till we get there if it'll fit....
We've had caravan holidays 3 times with a travel cot (not with park though)..
first time we had the cot in the lounge area, but only there a couple of nights and dd1 was 4 months and would sleep anywhere!
second time we asked very nicely and had them unscrew the bed to make space for the travel cot
thrid time we had to put the travel cot on the middle of our bed for dd3 to go to sleep in, then transferred her to a matress (really one of the cushions off the sofa!) on the floor by the side of our bed once asleep. She was 18 months old at the time and slept through this every night.
thank you also megbusset and bumpybecky. we've wimped out and gone for a cottage
tis more expensive, but it also has a bath (ds hates showers!).
the thought of worst case scenario put me off too much. plus, as we're hoping for dc2 next year, it may be our last holiday for a while (and it's been two years since we last went away), so we've spent a bit more for a cottage.