I know some (most) people will think I am a stick in the mud here,
but, using gwenview (4.4.5), how do I turn off "preview" functionality
(I don't want to see previews of ANYTHING - EVER, EVER, EVER), and how
do I set the view mode to "details" (with a generic icon)?

Since gwenview is intended as a picture viewer, I don't think they are going to give you an option to not see pictures. Why can't you just use dolphin?

I liked the way the old picture viewer (in kde 3) worked. :(

I want the ability to see files in the detail mode (so what if
they are picture files?), and not as icons.

I guess dolphin is tolerable (IF I turn off the "information panel -
UGH!).

One more question about turning things off. Is there someway
(preferably globally rather than per application) to disable the
collection of any kind of "recent" folders or files? I just detest
any behavior like that.

I suppose I could start by changing the owner of:
~/.kde4/share/apps/RecentDocuments
to some other user (with no read or write permissions),
but this really should be configurable.