Abstract: Forest-cropland sources can be allocated under a concentrated and contiguous orientation, particularly for coordinate regional food security and ecological sustainability. It is often required to effectively explore viable allocation in modern agriculture. In this study, a systematic framework was developed to integrate “suitability assessment-zonal selection-spatial optimization-effectiveness evaluation.” A case study was also taken as Shuangfeng County, Hunan Province, China. First, the forest-to-cropland and cropland-to-forest areas were identified, according to practical regional conductions. A four-quadrant approach was utilized to simultaneously consider topographic slope factors and cropland suitability. Land parcels were then categorized into the four quadrants. The areas suitable for cultivation were also determined, while the zones in need of restoration to forest cover were identified for soil erosion control. Second, a fine-scale “area balance-quality priority-spatial contiguity” optimization model was constructed for the spatial contiguity and accessibility of the allocation units, specifically under the constraint of cropland retention and red-line policies. Finally, the spatial optimization was then evaluated from the quality and spatial layout dimensions. The results indicate that: (1) Cropland with I-III suitability grades accounted for 63.24% of the county, providing for a solid foundation for agricultural production. Some areas remained the suboptimal to require targeted improvement; Meanwhile, the forest with I-III suitability grades accounted for 73.39% of the total forest area. (2) In terms of spatial distribution, the high-density areas of cropland-to-forest conversion were concentrated in the central Gantang and Yintang Town, the western Zoumajie Town, and the central-southern Yongfeng Town, with conversion potentials of 1359.02, 1 337.10, 1 027.72, and 962.68hm², respectively. High-density areas of forest-to-cropland conversion were distributed in the central Huamen Town, the southwestern Qingshuping Town, the southern Xingzipu Town, and the eastern Heye Town, with conversion potentials of 1 073.42, 1 069.98, 1 052.86, and 1 012.08 hm², respectively. (3) The proportion of grade I cropland increased after optimization, indicating the marked potential in the regional agricultural production. The spatial layout of forest and cropland shared a “cropland downslope, forest upslope” pattern, fully meeting the optimal allocation of agricultural resource in the hilly regions. Furthermore, the overall landscape metrics were also improved after optimization. The total number of fragmented forest and cropland patches was reduced in landscape fragmentation. Simultaneously, the spatial layout regularity and the spatial connectivity were strengthened effectively. The cropland quality was enhanced to optimize the spatial landscape patterns for the area balance. Consequently, this framework can effectively support decision-making in regional land-use policy and the county-level spatial planning. The findings can also provide the valuable practical reference for the forest-cropland reallocation to mitigate land-use conflicts in similar hilly regions. Actionable insights can also offer special spatial planning for cropland protection and national greening. These contributions are expected to foster regional food security and long-term ecological sustainability.