I think that's a much better plan to work with, well done. The one thing I would point out is that it looks as though you are still taking your timings straight from Google map estimates. It doesn't alter your trip goals, but it's best to prepare yourself for it all to take longer than you are expecting it to. I always allow extra leeway as it feels better to be ahead of schedule rather than playing catch up all the time. As I'm not sure where in Philadelphia you are starting I will use St Louis to Salina as an example, that will likely be 7 hours with a short stop, Richfield to Reno 9.5 hours and so on. One tip would be to try and stay to the West side of major City's, so that you are heading away from the morning rush that's heading into the city.

If you have any other questions, please ask. If not I hope you have a great trip, but please drop by and let us know how it went.

Dave