Finally got out to a field (gas pipeline area). It is next to a soccer field. Loads of milkweed there. I cut a bunch back so there'd be new growth. No large caterpillars. I found 6 first instar, 1 second instar and 3 eggs. I saw a Monarch fly by, but couldn't determine sex.
I'm going to try to see if the company that mows that area will delay mowing. Last year, I think they mow late Sept.