This paper focuses on problems associated with the deployment of automatic agents for last-mile delivery. We propose a framework and methodology to systematically evaluate and compare different hybrid strategies. Performance metrics in agent noise, delivery time, energy consumption, coverage rate, package throughput, and system costs are defined rigorously and modeled mathematically. Using the methodology, we conduct a case study in the city of Boston for four agent delivery strategies, including a hybrid strategy proposed in this paper. The proposed strategy utilizes available space in public transits' cabins during off-peak hours to relocate the agent traveling start locations. Simulations and analyses show that hybrid strategies outperform the Agent-Only delivery strategy in terms of noise exposure, energy consumption, and coverage rate. The performance of hybrid strategies highly depends on the characteristics of the ground transportation methods accompanying agents. Thus, the methods of ground transportation should carefully be examined and selected for each case and strategy in real-world applications.