I did a cache and davlik cache wipe before flashing the kernel.
Then I let rebooted and let the phone settle.
Since I ran the ROM for a day or so before flashing the kernel, I couldn't tell you if it is ok to flash both at the same time. I'd install the ROM and let it settle and then flash the kernel, but I am pretty new to this.
I just like to flash one thing at a time so I can pinpoint any issues if they happen to arise.