I own a vacation rental in the Pocono Mountains in PA and it's by far my favorite of my rental properties.
To answer your questions:
1. Have you been able to create an automated system for booking?
I could if I wanted to - but I do not. I like to be able to speak to potential guests and be a bit pickier about who stays in the home. There are automated services out there however. I just choose not to use them and it's worked out well for me - I have avoided some potential disasterous tenants.
2. Do you use a management company and if so what do they charge?
Nope I do everything myself. I am not local, either. It's actually not hard to do it yourself - as long as you find a great cleaner and maintenance/handyman - you're set. My cleaners do way more than just clean - they are my eyes are ears for the home.
3. Do you advertise aside form VRBO.com, Homeaway.com & vacationrentals.com?
Just craigslist and a few other free sites including my own site. The bulk of my rentals come from homeaway.com however.