Aaron,
Thanks so much for your response, it got the wheels turning… what I discovered is that I hadn’t even created the custom permalinks yet, which is usually the first thing I do. Once I created the permalinks, which created the blog’s .htaccess file and parameters, everything worked fine. I was able to leave my main site’s .htaccess file intact with the same redirects, and it works in harmony with the blog.
I’m glad I figured that one out because it was driving me nuts. If I would have only known that it was that easy. Now I feel stupid, but at least the blog is working right! Thanks for your help.