Oh, K3vin, K3vin, K3vin... surely you know that the capacitor itself does not create the timeslip. It creates the field that the localized area is encapsulated in. And it's not so much that the field travels through time, but rather, it is the field that holds the localized are solidly in place, outside the flux of time. Time does not stop and so flows around the field generated by the capacitor. That's why the Delorean was so important! The all aluminum shell of the vehicle was perfect for the conduction and containment of the field. It's likely that some other metal would have done as well, or perhaps some sort of metalicized polymer, but let's face it... why re-invent the wheel when you have a perfectly good Delorean sitting right there in Doc Brown's shed?

Moving through the time slip, forward and backward is as easy as tacking to the wind, maneuvering on the river, upstream or downstream.