How to customize Magento as CMS system (1.5.0 CE)

Before install:
1. Go to app/etc/modules, edit Mage_All.xml, only set the following modules active.
Mage_Core
Mage_Eav
Mage_Page
Mage_Install
Mage_Admin
Mage_Adminhtml
Mage_Cron
Mage_Directory (need by customer module and system country option)
Mage_Customer
Mage_Log
Mage_Backup
Mage_Poll
Mage_Rating
Mage_Cms
Mage_Newsletter
Mage_GoogleAnalytics
Mage_Media
Mage_Contacts
Mage_Dataflow (need by customer)

2.Only keep the following modules (set others as inactive)
Mage_Api.xml
Mage_Compile.xml
Mage_Connect.xml
Mage_PageCache.xml
Mage_Widget.xml

3. Install Magento as normal, if success, there will be 110 tables...(less)
4.Go to Magento backend, will throw errors because admin dashboard uses some features of sales (order, product, etc).
Rewrite Mage_Adminhtml_Block_Dashboard
rewrite the construct and _prepareLayout

public function __construct()
{
parent::__construct();
//set to different template
$this->setTemplate('cmsdashboard/index.phtml');

}

protected function _prepareLayout()
{
      //nothing
}
5.Widget not work, need rewrite.
In Mage/Widget/Model/Widget/Instance.php,remove or comment the following code:
76-79
/*foreach (Mage_Catalog_Model_Product_Type::getTypes() as $typeId => $type) {
            $this->_layoutHandles[$typeId.'_products'] = str_replace('{{TYPE}}', $typeId, self::PRODUCT_TYPE_LAYOUT_HANDLE) ;
            $this->_specificEntitiesLayoutHandles[$typeId.'_products'] = self::SINGLE_PRODUCT_LAYOUT_HANLDE;

In Mage/Widget/Block/Adminhtml/Widget/Instance/Edit/Tab/Main/Layout.php
comment or remove 155-181

/*$options[] = array(
            'label' => Mage::helper('widget')->__('Categories'),
            'value' => array(
                array(
                    'value' => 'anchor_categories',
                    'label' => Mage::helper('widget')->__('Anchor Categories')
                ),
                array(
                    'value' => 'notanchor_categories',
                    'label' => Mage::helper('widget')->__('Non-Anchor Categories')
                )
            )
        );
        foreach (Mage_Catalog_Model_Product_Type::getTypes() as $typeId => $type) {
            $productsOptions[] = array(
               'value' => $typeId.'_products',
               'label' => $type['label']
            );
        }
        array_unshift($productsOptions, array(
            'value' => 'all_products',
            'label' => Mage::helper('widget')->__('All Product Types')
        ));
        $options[] = array(
            'label' => Mage::helper('widget')->__('Products'),
            'value' => $productsOptions
        );*/

        }*/

Done! Enjoy!