With the increased availability of low-cost natural gas, the co-conversion of natural gas and biomass-to-liquid fuels has attracted attention from industry due to its potential for improving liquid fuel yields while lowering greenhouse gas emissions. In this paper, we provide an understanding of Fischer-Tropsch kinetics, improvements in processing strategies for hydrocarbon production, and of its impact on cost for the co-conversion of natural gas and biomass-to-transportation fuels. Studies that investigate the effect of Fischer-Tropsch reaction kinetics on techno-economic analysis can be used to develop process models that consider reaction stoichiometry and account for the effect of the paraffin-to-olefin ratio. We consider two processing scenarios: (1) one that does not employ a hydrocracker, and (2) the other where a hydrocracker serves as an integral part of the process scheme. Our analysis shows that co-processing natural gas not only facilitates the economic benefits of converting biomass-to-liquid fuels but also facilitates flexibility in process integration. The resulting minimum fuel selling price ranged from $2.47-$3.47/GGE (gallon gasoline equivalent) without the hydrocracker and ranged from $2.17-$3.60/GGE with the inclusion of the hydrocracker, for a 50 million GGE hydrocarbon fuel production facility and for varying blending ratios for biomass from 0-100% with natural gas. The hydrocracker helps to increase the production of diesel and jet fuels substantially, with carbon efficiencies of 50% attained for a chain growth probability of 0.87. The cost penalty comes from the capital expenses of the hydrocracker, and the expense may not be offset with hydrocarbon yield improvement.