Followup to earlier posting. I wrote a version of the php-based page replacing the php elements with hard-coded html and the DreamWeaver Design view was no better at displaying the page, so the problem has nothing to do with php. The file validates and appears fine in browsers.
I then grabbed a copy of the static html as provided by the web developer office and opened that in DreamWeaver, and even that was pretty well unusable in DW design view.
Blair called to say that the central web developers might help port material from existing template-based sites to the new CMS, but I expect that applies only if no modifications have been made to the templates - and all the sites we've had anything to do with violate that assumption, as the templates as provided are difficult to work with.