Free Shipping to US and Canada special on select items?

I'm running ZC 1.5.1 and looking for the smartest way to offer a free shipping special to US and Canada on a per-item basis.

I'm pretty adept at tweaking php but unsure which angle to come at this from.

What happens if you ship any of these Products for free shipping to somewhere else?

What shipping modules do you have installed?

I have FedEx Ground and Express, USPS and Store Pickup. There seem to be two free shipping modules...

Free Shipping Options
FREE SHIPPING!

The FREE SHIPPING one has a zone dropdown with only California as an option. How would I add selections to that drop-down, for example having US & Canada as one option or 'the' option?

You can build a Zone Definition for the US and Canada for the Free Shipping Options freeoptions ...

However, you are saying you only want this on "some" Products ...

Is there something to identify these Products that get Free Shipping for the US and Canada?

There are several ways to identify these Products for Free Shipping and to only work for your Zone Definition of the US and Canada ...

Is your definition of the US ALL of the US or just part of the US such as US 48 plus DC?

Yes, occasionally the store wants to offer free shipping on 'select' items, but only to US and Canada. I'm not sure how US is defined... whatever the default is(?) I've read threads discussing running scripts to define a zone for "US and Canada" and a zone for "Everywhere Else" but the process seemed complicated... or at least more complicated than I should think it would be.

Is there a way to add options to the product page here?:

Always Free Shipping:
Yes, Always Free Shipping
No, Normal Shipping Rules
Special, Product/Download Combo Requires a Shipping Address
Free shipping to US and Canada Only