Validating dates based on select field?

Hi All,

I have a form that I am trying to fulfill the following scenario. Does anyone have any advise/solutions? I have a registration form.

On the form are the following fields:

-US State Pulldown
-Country Pulldown
-5 Night Hotel Pulldown
-3 Night Hotel Pulldown
-Arrival Date (pop-up calendar)
-Departure Date (pop-up calendar)

I need the form to do the following:
* If I choose a US State from the pull down the Arrival Date on the calendar needs to be 30 days from todays date with no dates previous available. If it easier to do this with a mo/dd/yy series of dropdowns I am OK with switching it out.

* If I choose a Country from the pulldown the Arrival Date on the calendar needs to be 45 days from todays date with no dates previous available.

* If any hotel is selected from the 5 Night Hotel Pulldown then the calendar arrival and departure dates must be tested so the days are minimum of 5 days.

* If any hotel is selected from the 3 Night Hotel Pulldown then the calendar arrival and departure dates must be tested so the days are minimum of 3 days.

Any suggestions I am very VERY much open to!! THANK YOU!!!

Thank You Very Much,
Michael