BWV
DVC owner here...I stay primarily at BW, so am pretty conversant about the parking there. Anyone is entitled to park in that overflow lot, behind the Hess Station. But, it is a hike over to BW from there, and when you add in the time it would take to get to either Epcot or DHS from that lot, well..it's just too big an inconvenience for me. Not worth the money saved.
Same thing with parking at DTD...sure you can do it. But, the buses don't start running to the resorts early enough to get to a park for rope drop...maybe not even until close to 11:00!!! And it takes at least an hour, closer to 90 mins to go from DTD parking to a park. But, if that's what you choose to do, go for it.
As for parking at resorts and then heading to a park....can you do it? Sure you can. Are you supposed to? Jury is still out on that one. At some periods, throughout the year, there will be a sign up, at the resort parking lot area, that says parking is not provided for park access. This pretty much means you can't park there and then head off to a park unless you are paying to sleep at that resort...for that time frame.
Other times, no one will stop you from parking at a resort and then heading to a park. But, Disney only sometimes hands out 3 hr prking passes and they only sporadically tow cars. Yes, both things can happen, but they aren't the norm.
This 'discussion' has been done to death. It just isn't that big a deal. I only wish that when articles like this come out, they also made it clear that using 'alternative' methods of getting to parks when getting 'free' parking, is not very fast or efficient!!