Thanks to everyone for the replies. We called Brandon at Thomas Wildlife Control (916.500.9027) and I am SO glad we did. Brandon came out and carefully inspected the attic. He was up there for quite a while, and of course, I was getting nervous that maybe our attic was out of control and was going to be extremely expensive to deal with. He came down and said that on a scale of 1-10, with 10 being the most damage he had seen, our attic was (wait for it...) a 1.
For $650, he did a full exclusion process. He fully analyzed the inside and outside of the attic and sealed off every possible hole with a really fine steel mesh. I know that we could have done it ourselves for less, but honestly, it was worth it to have someone who knows the process do it right.
Terminix tried to convince us that not only did we need exclusion (for $1650...yes, a full $1000 more than we paid), but that we also needed a full attic overhaul--sanitizing and insulation removal/replacement for another $6900. Brandon took a bunch of pictures that showed that to be a ridiculous proposition. It would have been a waste of time and money. And this is from someone who does this all day, every day. Not only that, Brandon actually identified clearly the path that the rats had used to get in and where they were going in the attic. The traps that Terminix set were in the complete opposite end of the attic...no wonder they never caught anything. Brandon set 8 traps in the path they were actually using and so if any were in the attic before the exclusion process, he will catch and remove them. In the interest of disclosure, that was another $250, but honestly, totally worth it to us not to have to deal with it during the holidays. And his service is guaranteed.
And yes, we ended service Terminix.