how can i add extra parameter to edit post link?

The get_edit_post_link filter lets you modify that value. This is applied any time get_edit_post_link function is called, which admin uses, as well as themes on the front end.

function wpd_edit_post_link_filter( $link, $post_ID, $context ){
    if( 'room' == get_post_type( $post_ID ) ){
        $link = $link . '&fubar=baz';
    }
    return $link;
}
add_filter( 'get_edit_post_link', 'wpd_edit_post_link_filter', 10, 3 );

You can use the $post_ID to fetch info about that particular post, and get_current_screen might be helpful to decide when to apply the filter.