By great good luck, I did speak directly to Richard Bartrop's sister today.

Among other things, she was touched and gratified by all of the expressions of sorrow from the fandom as to Richard's passing. She, apparently, was a fan of his work.

She told me that in a few weeks, she's going to be going to Calgary to sort through his materials. So my sketchbook may, in fact, be found (I gave her a description). She did tell me to ask around if anyone else has materials that need to be returned. If anyone does, I can forward requests to the sister, since I have her email.