The K1 chip has a blob-free boot (unlike the newer chips AFAIK) except for the USB-based flash programming / recovery mode, so for the initial installation you'd need to manually flash the eMMC somehow if you don't want to run any proprietary code.
And yes, CUDA isn't supported by the open drivers. Other than that, I've heard Nouveau works relatively well. Though I'm not still sure if the open source graphics community has figured out a way to get stacks like Xorg or Wayland/Weston running without hacking the source on architectures where rendering and scanout are done by different DRM devices.
And to get good use out of the GPU (one of the main selling points for this platform), you'll want to use the Nvidia proprietary driver.