I upgraded VirtualBox to 4.3.0 to work as it apparently addresses the network issues that I was having with running earlier versions on OS X Mavericks.
However, a new nuisance popped up - one that forces me to do a hard shutdown when closing shutting down. Thankfully, the interwebs are experiencing the same issue and people much smarter than me were able to figure it out.
In short, my problem was that I had some old libraries in /Library/Extensions/ so I removed the VBox*.kext libraries. I also did a reinstall of VirtualBox just for good measure and so far so good. Now I can shutdown my laptop cleanly and run networked VMs. Yay!!!