the new PHP pages need links to/from the existing HTML pages. DW warns that files may not be found if in a different folder. Do I just ignore this and ensure that all files are uploaded to same remote folder? Or do I need htdocs in remote folder as well?
Rob it can be done that way. There are also a lot of users who try to keep it separate. They keep local files and then test in another location. The warning that is being received about a different folder is usually related to the paths. I explained this to another user here: http://forums.adobe.com/message/4224748 . It doesn't have to be in the same folder because DW can test the pages from anywhere. Matter of opinion at that point. Personally I use one folder for both, but it can be done either way.
I have decided to move everything to htdocs to have the complete site in one folder (and do some housekeeping while I'm at it). It seems better to do this now before I create a load of php pages.
But I think this subject could be explained better in the DW tutorials. I guess most newbies (like me) will start off with a static website and only think about adding dynamic pages later.
DB I agree with you 100% about the documentation. It's dated and not as useful and it could be at explaining the setup, but moreso with the errors. Plus the search function on these forums has never been stellar, so finding these old posts is usually done through a google site search rather than a forum site (ie: site:forums.adobe.com [search string here] - when you go to google search like that).