trt...if you are fit enough and you have the money, its very easy to do.
Nowadays, I am not sure I could do all that driving and I certainly can't afford it, but I am glad I did the road trip when I was 41.
Back then, it was rather difficult to find parts of the route. But I got myself some good books and some even better maps, and away I went. I stayed in cheap Motels most nights, and in a couple of famous original Rt 66 era ones.
I ate in truck stops, always the best when you are in America, as any road tripper will attest.
I can thoroughly recommend the following book by Michael Wallis :::
http://www.abebooks.co.uk/servlet/BookDetailsPL?bi=17486486942&searchurl=tn%3Droute%2B66%2Bthe%2Bmother%2Broad%26sortby%3D17%26an%3Dmichael%2Bwallis
So, all you need is a airline ticket for Chicago, a rental car, about £1000 in your pocket ( maybe less ! )
Don't forget the airline ticket back from Los Angeles !