Alot of good stuff. I would look into LD Comfort shorts, they also have alot of good info on hot weather riding, ie no powder or padded shorts and other cooling ideas. People can tell you all day long about works for them or what makes sense but when you are on the road it is what works for you that will get you through.
Things that work for me were the throttle lock, highway pegs, good seat, traveling at 5-10 over the limit (any faster for me is more physically draining). I also enjoyed riding at night especially in hotter months and as stated it is cooler, less traffic and more peaceful. I don't know about the rushing through gas stops or adding additional fuel tanks. You are going to want to get off that bike and the longer you can prolong that feeling that you have to get off the bike the more comfortable you will be. You can stop at mc d's and get salads and refill you ice and water and use the rest room.
The largest problem you are faced with is not the time nor distance but the time of year you are doing this. Lots of different views of mesh vs vented etc. You can siphon through all that but what you have to focus on is you and when you feel yourself weakening, fatigue setting in or other deviations from your norm you need to listen to yourself and pull off and either take a short break or get a room and a good nights sleep and recharge to ride again. Riding a motorcycle is a blast but it is also UNFORGIVING with no margin for error. Try to have fun and remember you primary goal is to live to ride again. Ride safe and have a blast.