Having a SIM card is so useful. We used this service where we also got our JR Passes and it worked beautifully. The heat is no joke. I got heat exhaustion partway through the trip. Definitely have an umbrella to block out the sun, a hat, or wear long-sleeved clothing to prevent direct sun. Mosquitoes are savage. That, with the heat, it's no wonder the fashion trend in Japan is long, loose, and flowy clothing. They definitely cover up there. Osaka is full of music. Don't eat in Dotonbori. See it, but for food, head over to Shinsekai. Shinjuku Golden Gai is so fun A++ recommend. The JR Pass does not cover Nozomi trains. Rush hour is intense, try to avoid as much as possible especially if you're like us and don't like squeezing in to trains. There are a lot of tourists in Kyoto, and they come in large tour bus groups. Pick areas you REALLY want to see, and go early. Nara Park, Fushimi Inari Shrine, and Arashiyama without tourists are gorgeous ...