The SPCA folks agree that it would complicate things to introduce Carter to Rex, too. Since he's leaving in a few days, we're going to wait until Kaitlin comes and collects him before trying to bring Carter home. Then he can come settle into the house with just Penny, whom he's already (more or less) gotten to know. I think we'll also need to wait a while before introducing him to Gloria, Molly's pit who visits frequently for dinner or a weekend. Carter reportedly does fine when he runs into other dogs while out for a walk, but might not react well to random dogs showing up at "his" house. Once he's comfortable here, we can experiment.
This probably also means no more visiting my parents with the dogs. Unless Carter turns out to be every bit as chill as Penny was, I'll need to find him somewhere else to stay when I visit them. Molly is happy to take care of the dogs (I take care of hers often enough), and Carter has other fans who've offered to help! They did fine with just Penny visiting last year for Thanksgiving, but both Penny and Rex last month was pushing it.
So, with Kaitlin likely to be picking up Rex at the end of the week, it'll probably be next weekend before I bring Carter home. Count on more photos to come. :-)