Dave Coverly is creator of Speed Bump. The rest of the interview: Intro, Parts 1, 2, 3, 4, 5. There's a "write your own caption" contest, too.
Are the words and the illustration equal in difficulty, or is one easier for you than the other?
At this point, they're about the same, actually. 
The words used to be easier, but after doing this for a dozen years, I'm very happy and comfortable with my drawing style now. And I love daydreaming - the best part of this job is that little magical moment when the elements of a joke collide into something organic and funny. Many of the cartoons need to be worked on hard to make them look natural, but sometimes they just make themselves known with almost no effort.
The only part of cartooning I'm not crazy about is the inking - thinking and sketching are great, but inking seems to have more pitfalls than upside.
