Download this plugin, http://wordpress.org/extend/plugins/theme-my-login/.
Install and activate the plugin, the user will not see the wp-admin login page from now on. Also to prevent the admin dashboard access, go to Setting->Theme My Login. Under the General->Modules tab, Enable Custom Redirection.
Now in the Redirection tab, for different roles you can set a custom landing page, which could be set to point to your homepage. So, after login, he will be directed to your homepage.
And use this small hack to hide the admin bar on top of the screen:
Go to Appearance->Editor->functions.php
Add this snippet somewhere:
//Snippet Begins
if (!current_user_can('administrator')) :
show_admin_bar(false);
endif;
//Snippet Ends
And there you go. :)