Modifying checkout form values via hook_form_alter

I would love to hear from the community on this.

wow that was a pretty silly mistake, glad you noticed that. Sadly I still haven't been able to push new values to items like:

$form_state['field']['#parents']['customer_profile_shipping']['#fields']['commerce_customer_address']['und']['field']['columns']['name_line']['default'] = 'test';

The answer is in altering $elements within the hook below. Address field does not allow you alter values or defaults directly in the form or form_state but rather in the addressfield_standard_form_alter :)

hook_field_widget_addressfield_standard_form_alter(&$element, &$form_state, &$context){
}

@John Pitcairn

Just as reference here is my code as how I was able to autopopulate the shipping/billing fields. You have to figure I'm dumping my custom values into the order array for portability.

function test_field_widget_addressfield_standard_form_alter(&$element, &$form_state, &$context) {

    if ($element['#bundle'] == 'shipping') {
        global $user;
        $order = commerce_cart_order_load($user->uid);
        if (!empty($order->data)) {

        $countrylist = array(
        'AT' => t('Austria'),
        'AS' => t('American Samoa'),
        'BE' => t('Belgium'),
        'BG' => t('Bulgaria'),
        'CA' => t('Canada'),
        'CY' => t('Cyprus'),
        'CZ' => t('Czech Republic'),
        'DK' => t('Denmark'),
        'EE' => t('Estonia'),
        'FI' => t('Finland'),
        'FR' => t('France'),
        'DE' => t('Germany'),
        'GR' => t('Greece'),
        'GU' => t('Guam'),
        'HU' => t('Hungary'),
        'IE' => t('Ireland'),
        'IT' => t('Italy'),
        'LV' => t('Latvia'),
        'LT' => t('Lithuania'),
        'LU' => t('Luxembourg'),
        'MT' => t('Malta'),
        'NL' => t('Netherlands'),
        'NO' => t('Norway'),
        'PL' => t('Poland'),
        'PR' => t('Puerto Rico'),
        'PT' => t('Portugal'),
        'RO' => t('Romania'),
        'SK' => t('Slovakia'),
        'SI' => t('Slovenia'),
        'ES' => t('Spain'),
        'SE' => t('Sweden'),
        'CH' => t('Switzerland'),
        'GB' => t('United Kingdom'),
        'US' => t('United States'),
        'UM' => t('United States Minor Outlying Islands'),
        'VI' => t('U.S. Virgin Islands'),
    );
            if (isset($order->data['self']['country'])) {
                if (array_key_exists($order->data['self']['country'], $countrylist)) {
                    $element['#address']['first_name'] = $order->data['self']['FirstName'];
                    $element['#address']['last_name'] = $order->data['self']['LastName'];


                    $handlers = array('address' => 'address'); //There are other formats, but this one will output the mailing address.
                    $context = array('mode' => 'form');

                    $address = array(
                        'country' => $order->data['self']['country'],
                        'name_line' => '',
                        'first_name' => '',
                        'last_name' => '',
                        'organisation_name' => '',
                        'administrative_area' => '',
                        'sub_administrative_area' => '',
                        'locality' => '',
                        'dependent_locality' => '',
                        'postal_code' => '',
                        'thoroughfare' => '',
                        'premise' => '',
                        'sub_premise' => '',
                        'data' => '',
                    );

//Now generate the render array, where $addressfield_object is your addressfield, of course
                    $address_rendered = addressfield_generate($address, $handlers, $context);
//Now all you have to do is use drupal_render to create the output, and voila!
                    $element['street_block'] = $address_rendered['street_block'];
                    $element['locality_block'] = $address_rendered['locality_block'];
                    $element['country'] = $address_rendered['country'];
//Override the country option list
                    $element['country']['#options'] = array($order->data['self']['country'] => $onepointo_countrylist[$order->data['self']['country']]);


                }
            }
        }
    }
}