Better prediction of the hydrologic cycle in permafrost-rich Arctic watersheds requires models that capture complex permafrost physics and model inputs at high spatial-temporal resolution. Though integrated surface-subsurface, coupled mass-energy transport models have been successfully applied to simulate permafrost dynamics at local polygonal and hillslope scales, these models have not been used at the scale of watersheds or full river basins. Largely this is because three-dimensional simulations have been found computationally infeasible. To address this issue, we proposed a novel model conceptualization to scale up permafrost simulations to full-river basin scales. The core idea is to combine strategies of watershed splitting and hillslope parameterization, followed by hillslope scale modeling and external river routing. We applied this model conceptualization to the Sagavanirktok (Sag) River Basin located in the North Slope of Alaska. The full basin was delineated and split into 6498 sub-catchments according to the geomorphic features, and each sub-catchment was parameterized into an equivalent 2D hillslope. We simulated the dynamic freeze-thaw cycles for each hillslope using the Advanced Terrestrial Simulator (ATS) and the simulated hillslope runoff was then routed by the Model for Scale Adaptive River Transport (MOSART). Early applications of the model found significant bias in stream flows during snowmelt and the following freshet period, mostly caused by inappropriate infiltration-runoff partitioning. This issue was markedly improved after revisiting the physical model representations such as relative permeability under freezing conditions. Results demonstrate that the proposed model conceptualization can be successfully applied to predict cryo-hydrologic change in full-river basins.