Installing Vista 64bit, then looking at WDK

I'm finally ready to give Vista 64bit a look-see. I'll dual-boot it with WinXP Pro 32bit.
I've set up the partitions and am ready to do the installation. My MoBo is 64bit capable.

Question:
There should be no conflicts between the 32 and 64 bit OS's. Right?

I expect a few (many?) driver problems this early in Vista's existence.
I've acquired the WDK from MS and intend to give it a look once Vista and it are installed. I'm hoping that I may be able to use it to make up drivers for some of my peripheral h/w. Although, I may be biting off just enough to choke on. Time will tell.

Question:
Is anyone familiar with the WDK who can offer advice if needed?

Thx