CVS aware Drupal 6 - gotcha: YES IT DID - TAKE 2!
I only got as far as entering the database details on the CVS aware copy of Drupal 6 downloaded yesterday. The install.php stalled with a repeated SQL error. There was an additional directory level that I'm sure was not the issue; anyway, I deleted and started again. This time - using CVS again - it worked OK. The Drupal 6 install was very smooth. I'm sure this isn't the end of Drupal-CVS issues though, judging from comments on the Drupal site.
So far I've downloaded some contributed themes and am running through the modules. Quite a few of these are not compatible with Drupal 6, so I can appreciate how developers rely on the stable and more fully supported Drupal releases.
If you stand solely on the bleeding edge then you will bleed. Reaching for the psychological elastoplasts I'll try and carry over the drafted pages which are still in the Drupal 5 test site. I don't look f/w to redoing the menus..., but the repetition is essential learning. Must dig into the modules in Drupal 6 and revisit those already enabled in Drupal 5.