Congrats on qualifying for Hawaii!
Racing back to back Ironman is something I have done for a good few years now! ..so it is possible!
I would advise you not to rest completly at any time. Since you qualifyed for Hawaii at Canada your body must be going ok, so just keep it moving, spend 1 week now doing easy and short recovery sesions then 3 weeks with some of your normal training. And 2 weeks for your normal preparation into a big race,
Hope that is of some help, See you in Kona!