Yes Brendan, I did know him and so have got 11ac and all the top half from the hints given. I've been held up by the wrong answer to 18ac, which I have now got and possibly 22ac. I have ?T?E?D?O
I suspect 15d is related to theme though I can't parse it.
Can I have a hint please for 20d (C???O?), 19d M?E???
By the way Brendan, I did finish last week's fiendish marathon and even plotted all the states out on a map to match the grid. But I wish, like ChrisE, I hadn't bothered as it took me three days and I had other things to do. I did manage to fit in some gardening, but other things slipped. I think I'm suffering from 1d.