RewriteCond %{REQUEST_URI} ^/drupal//.* RewriteRule (.*) /$1 [L]
I'm halfway there. Or three quarters of the way there. Nine tenths. Now what I've got is that the menus link to "/drupal//news/" and the page loads the content that also appears at "/news/" sitewide. Which of course has forced me to realize that what I really want is not URL rewrites, but actual redirects. Still, this keeps the site intact as a whole so it is plenty good enough.
I believe adding in an R will change it to a redirect instead of a rewrite:
RewriteCond %{REQUEST_URI} ^/drupal//.* RewriteRule (.*) /$1 [L,R]