I can't really give you a comparison of 65 vs. 75. We have always taken 75 straight through to Florida. It is 1,176 miles from our house to our campsite at FW ...... can you tell we have done this a few times? We travel exactly 60 mph and it takes us about 22 hours to get there (barring some bizarre accident on the way there). We always take 285W around Atlanta, as we always seem to land there around rush-hour. It is a bit easier to navigate than 75. Other than that minor change, we stay on 75 until we reach the FL turnpike and 27. Your tow vehicle seems like a good choice for what you are pulling, so you should not have any real problems ...... have fun!