Our principal focus in the present work is on one-dimensional kink-antikink and two-dimensional kink-antikink stripe interactions in the sine-Gordon equation. Using variational techniques, we reduce the interaction dynamics between a kink and an antikink on their respective time, and space (the latter in the case of the two-dimensional stripes) dependent widths and locations. The resulting reduced system of coupled equations is found to accurately describe the width and undulation dynamics of a single kink stripe as well as that of interacting ones. As an aside, we also discuss two related topics: the computational identification of the kink center and its numerical implications and alternative perturbative and multiple scales approaches to the transverse direction induced dynamics for a single kink stripe in the two-dimensional realm.