In this article, we present an alternative method for simulating charge transport in disordered organic materials by using a buffer lattice at the boundary. This method does not require careful tracking of carrier's hopping pattern across boundaries. Suitability of this method is established by reproducing the field dependence of mobility, carrier relaxation and carrier diffusion in disordered organic systems obtained by simulating the charge transport for the full length of the systems along the field direction without any boundary condition. The significance of the buffer lattice is emphasized by simulating field dependence of mobility without using a buffer lattice, which results in negative field dependence of mobility (NFDM) at low field regime due to the extra bias the carrier gains from the neglected hops at boundaries along field direction.