Advice on final 4 weeks before 10K with vacation?

Have a 10K swim Aug. 19. I've been doing 4-5K twice a week in the pool for a few weeks, and the last four weeks have gone 3, 4, 5, and 4 (no wetsuit) miles in the ocean. I am confident I can finish based on today's fitness (and it's a surf exit/entry every 1.2 miles format). Going to be away on vacation the remaining 3 weekends, near a warm (78 degree) ocean, so no issues having access to OW swimming, although nutrition might be different from my current 65 degree temps..... Other than last weekend where I took a gel on the 4 miler, I have not been taking any nutrition or fresh water and max swim has been 2:15. For the OW distances, advice as to what distances to swim the next three weekends, and how to alter training for the temps?