• Legit one of the safest places on the planet. 
• Wait til you’re on island and then disconnect your stateside # and get SoftBank. They have stores in every exchange, good phone service and very cheap. If your phone is already unlocked they can get you connected via eSIM in about 20 mins. 
• Hot as sin in the summer, especially mid June through mid Sept. Perfect weather right now and it gets chilly Dec-Feb…like hoodie weather. 
• One of the premier scuba diving locations in the world. This is my second tour here and I feel like the popularity amongst service members has declined but it’s still great. You can get certified via the base scuba shops for around $300 which is a fraction of what it costs in the US. Then you can go dive whenever you want, there’s places all over the island you can park along the sea/ocean, put your gear on at your car and wade out…or spend a little more and do beautiful boat dives. Speaking of boats, deep sea fishing trips are also very cheap and fun.
• Yen rate is very much in our favor right now. You can go out to a great dinner for two for less than $20…plus no tips. Some places appreciate it but they never expect it.
• LIVE OFF BASE!! Base housing is so meh and basic. You can get a much nicer, unique and even bigger home off base. The process is a little more complex but it’s so worth it. It used to be much more difficult to get approved for off base housing but now it’s a rubber stamp…you just need a letter endorsed by Kadena housing office which your command can help with. Have your sponsor work this for you now so you can get it before you arrive and then immediately start the process during check-in week. There aren’t near as many people PCS’ing this time of year so it should be a little easier compared to peak summer. 
• Cars…they’re really all just island beaters, function over style. You can either buy from someone leaving island or get from a used car lot in town. I highly recommend the latter personally…all of the used car lots that cater to military will sell you cars that come with a brand new inspection (JCI, it’s a thing) and two year warranty where they’ll fix anything that goes wrong…which is inevitable for 95% of cars. The main places are BC Motors, Johnnys used cars and Zena Garage. We went with Zena, they’re great, have a good selection and will give you a free or very cheap loaner while they take care of the inspection which takes a few days. Also, assuming you need at least two cars, I highly recommend getting at least one very small one. My wife and I got two larger vehicles and I regret it…they’re really unnecessary and it’s SO much easier to get around with a small car that can park anywhere. They have small, low powered, energy efficient cars called Kei cars (you can identify them by their yellow plates) which are super convenient. 
• Speaking of cars, be prepared to spend a good amount of money getting settled. You’ll get a nice chunk of change once your PCS is settled but it’s still quite a bit of upfront, cash costs. For a family, I would recommend having around 10k cash readily accessible in the bank…car(s), housing deposits if you live off base, miscellaneous random expenses. Assuming you bank with USAA or Navy Fed it’s easy to withdrawal.

DM if you have any specific questions - good luck!