Not that I'm aware of. They don't want people parking there for the theme parks. You could walk through Downtown Disney to get there if you needed to enter the parks, though. Or use the Monorail station which is closer to where you'd be entering Downtown Disney.
I'll add a caveat that I don't endorse breaking Disney's rules. Depending how long you're planning to spend in the park, you might end up actually spending more to be parked in the Downtown Disney lot than if you had just paid to park in, say, the parking structure ($35 vs $66 maximum in DTD).