I liked the picture the OP painted with his detailed question. If he had been concise most people here would have asked all the questions he covered in the OP. And this thread would be 12 pages long.... just saying.
I totally agree that most dealerships seem to have a lot of salesman just standing around with nothing to do all day. If you have a HUGE volume of foot traffic I guess internet technology isn't for you. But if you want to move units you will take the time to answer emails and develop a relationship with someone who might purchase from you.
I can't see it taking more than 10-15 minutes to walk the lot armed with the questions and lay eyes on the unit. Seems simple to me.
P.S. - Most car dealers now even have a dedicated "internet sales" person who understands how the internet benefits dealers. The last time I bought a car the internet sales guy had 4 people waiting for him.... and the "regular" sales guys were sitting around looking jealous that the last 4 people who walked through the dealership's doors already had an established relationship with someone and, therefore, were not "free for the taking".