When I bought my 08 KLR this past summer, I could not do more than 30 miles without getting numb is some places and hurting badly in others. So, at the urging of a friend he said to cut out the stock foam and replace it with 8# carpet padding. I did just that, 4 layers of carpet padding later I have a very comfortable seat. All it cost was the glue and a 24"x48" piece of carpet pad and now I can go all day on it.
My work is only .5 mile from my house, so I do not commute most days because of the time it takes to put on and take off the gear... Just not worth it for a 2 minute ride. On the weekends and evenings when it stays light after 6, I ride as much as possible.