In this study, we used a multi-scale modeling approach to explore charge transport in conjugated organosulfur polymers for lithium-sulfur batteries. In particular, the focus has been set on the PTBT polymer, which has been extensively studied as an alternative cathode material. By using classical molecular dynamics, for which we re-parametrized important force field parameters based on density functional theory calculations, we simulate the self-assembled aggregation of polymer chains with different regioregularity. We find that the polymer chains can form crystalline phases only for a regioregular head-to-tail/head-to-tail (HT-HT) regularity, whereas, for a head-to-head/tail-to-tail (HH-TT) regularity, the system does not show any long-range order after annealing. We can explain this structural difference by the increased steric constraints between neighboring TBT units within individual polymer chains in the HH-TT phase. Experimental X-ray diffraction measurements confirm the existence of crystalline phases in the electropolymerized PTBT, which we can relate to our predicted HT-HT crystal structure. We employ electronic structure theory to calculate the band structure and density of states of the different structural phases. It is observed that the polymer shows a semiconducting behavior. Further, we see how the structural disorder in the HH-TT phase leads to an energetic disorder that can potentially limit the charge transport herein. Our calculations of conductivity as a function of charge carrier density offer a first quantitative approach to estimating the intrinsic limit of the band-like mobility of the HT-HT phase along its crystal directions. Our results are in agreement with recent mobility measurements of similar crystalline thiophene-based polymers.