"Pickman's Model" is the second H.P. Lovecraft story filmed for Night Gallery (the other being "Cool Air"), and sadly, like nearly all Lovecraft adaptations, it loses something in the translation. In this case, the original story has been radically altered, and the creeping buildup to the real zinger at the end of Lovecraft's work completely lost. I recommend reading the original story (you can read it for free online).
That said, this episode and its adaptation aren't without merit. Their "spin" on the original is at least entertaining, and succeeds in conveying some idea of the skin-crawlingly horrific depths which Lovecraft could plumb. "Dear Departed" is also enjoyable. It's refreshing to watch something with absolutely no CGI.
On a side note, I for one never get enough of television (and film) period pieces of the 60's & early 70's. They have such a neat, unique character, between the color film and the anachronistic touches...plus you're looking at a small fortune worth of antiques in some of those interiors.
I recommend Night Gallery's "Cool Air", a more successful (and truer to the original) Lovecraft adaptation.