Checking out these sites on Google Maps gives you a good idea of what to expect, and from there it really boils down to what you're looking for.
As far as long travel days vs short, it also depends on whether the trip is about the destination or also about getting there. We have three kids 7 and under and we've done it both ways, peaking out at 15 hour tow days. A good example of a destination trip in our case is Disneyland, which was the 15 hour tow I mentioned. The point is to take the kids to the amusement park, zoo, etc., not dink around with them in Nowhere, Nevada and risk having to explain what a brothel is. By contrast a trip to the Oregon coast is through lots of scenic country and we have family along the way - I'd be more inclined to take my time in that scenario and add some travel days.
So again, it just depends.
