As far as the four hour ride goes just take breaks when you feel the need and don't push until you are uncomfortable. Wife and I have been doing this long travel stuff for 40+ years with many 700 to 800 mile days on two and three wheels. Now that we are both retired we don't push like that anymore, but a 500 mile day is easy for us. Frequent short breaks and hydrate, hydrate, hydrate, plenty of water even if you don't feel thirsty. We have snacks or a very small meal while on the road and save a bigger meal for when we get off the road for the day. That is just more comfortable for us. I don't carry spare parts or a bunch of tools anymore. Credit card and a cell phone and have never needed those. What I have needed was a tire repair kit. I make my own because I don't much care for the pre setup stuff. I carry the rope plugs with the tools to install them and a small 12v air compressor. Some like the rubber plugs, but I have had them fail twice over the years and will never use them again. I have never had an ugly rope plug let me down. Enjoy the ride, take back roads if possible, your not going to see America on a stupid freeway, relax and smell the roses.