We present in this paper a novel framework for the design of a modular and adaptive partial-autonomy wheelchair. Our design in particular aims to address hurdles to the adoption of partial-autonomy wheelchairs within general society. In this experimental work, a single assistance module (assisted doorway traversal) is evaluated, with arbitration between multiple goals (from multiple detected doors) and multiple control signals (from an autonomous path planner, and the human user). The experimental work provides the foundation and proof-of-concept for the technical components of our proposed modular and adaptive wheelchair robot. The system is evaluated within multiple environmental scenarios and shows good performance.