I upgraded the condo site to Drupal 4.7 last night, since it uses a standard theme and only a few additional modules (event & image). I came up with a good strategy for upgrading, although it probably won’t work on a web host other than DreamHost.
1. First I copy the site contents & database to my Mac and do the upgrade script.
2. I set up a test subdomain under the same user as the main site with the site contents in a different directory. Of course the PHP configuration should be exactly the same.
3. I set up a new MySQL database and load it from a dump of the upgraded database.
4. I upload the new site contents to the test folder & make sure it’s setup to use the new database.
At this point test.mysite.com should be working. Once everything works, I swap the original & test directories. Now the main site will be running the upgraded software with the new database and the test subdomain will be running the old. I can simply leave the new database in place and delete the old one when I no longer need the old site.