Steps to debug on a blank screened wordpress install

I’ve been given an old WordPress installation to setup on a new server. After setting wp-config.php and the values for the URLs in the db, wp_options.siteurl and wp_options.home (the usual process I do for something like this) I just get a blank screen on Safari, on Chrome I get

The website encountered an error while retrieving
http://domain.name/. It may be down for maintenance or configured
incorrectly.

I can access http://domain.name/wp-admin and the initial login splash page loads. But hitting sign in causes a similar error to what happens when accessing the front page.

There seems to be a lot of plugins installed for this setup. Wondering what the best steps would be to find out what the root of this problem would be.

I’ve tried setting debug on in the config by doing this, but it accomplishes nothing. I think something is telling the site to redirect somewhere near the beginning of everything:

if ( isset($_GET['debug']) && $_GET['debug'] == 'debug') define('WP_DEBUG', true);

1. Add the following to wp_config.php:

   define( 'WP_DEBUG', true );
   

2. Reset the Plugins folder

3. Revert to the default Theme (currently Twenty Eleven), using a similar method to the Plugin-reset step (just be sure that the only Theme available in /wp-content/themes/ is twenty-eleven)
4. If your site is restored, great! If not, you likely have some sort of server or database configuration issue. In either case, knowing the exact debug/error message returned will be necessary in order to troubleshoot further
5. Assuming your site is restored, begin to rebuild it
6. Restore/activate your Theme. If you get a WSOD, your Theme is the problem. Report back any Fatal Error messages you get
7. Assuming your Theme activates fine, and your site is still up, begin restoring/activating your Plugins, one-by-one. If you get a WSOD, you have identified the problematic code. Report back any Fatal Error messages you get