Hawaiian Tropic is great, but you still need to start with a high-ish factor if you dan't tan naturally.
One bit of advice is ... keep moving.
If you stay in one position, the sun if focused on one bit, and you are more likely to burn. If you are moving around, each bit moves in and out of the direct sun, and does not have so much time to burn.
Will you have anywhere secluded where you can strip off altogether? Nothing feels (or looks) better than having a good bum tan. And once your bum has tanned once, it tans more easily next year.