Andrew
It's been two years so not current but we were there for a Spring weekend in late March or early April and it was OK. All the above posts describe it properly - I'd just add that as it's on the highway and most of what's nearby will still be closed - the season doesn't begin until late May - it can feel a bit lonely. That may be good or bad depending on what you like.
That said, Spring and Fall are the only time I'll go to Cape Cod, The summer tourist traffic is unbearable to all, I guess, except the people stuck in it.
In terms of Platinum treatment I doubt there's much to upgrade you too - which is better: a view of the road or the parking lot or the woods? Breakfast was good and again, if memory serves, they'll even wash your car for you but given the property, there isn't much they can do. If Chillingsworth in nearby Brewster (Rt 6-A) is open you'd likely enjoy dinner there - it is consistently rated one of the best restaurants in Massachusetts.
New England weather is completely unpredictable. Several years ago we had 30 inches of snow on April 1st. It could also be in the 70's. Our spring comes much later than in the UK - April here is roughly February there. And as Cape Cod is a peninsula, the water both moderates and exacerbates the weather. It is generally more moderate in temperature than say, greater Boston but at the same time more subject to the effects of wind and water.
All of which is to say if it's sunny and mild you'll likely enjoy wandering around more than if it's dank, cold and raining.
Which it'll be is anyone's guess.
[This message has been edited by Bostom (edited 02-11-2003).]
[This message has been edited by Bostom (edited 02-11-2003).]