As robots that follow natural language become more capable and prevalent, we need a benchmark to holistically develop and evaluate their ability to solve long-horizon mobile manipulation tasks in large, diverse environments. To tackle this challenge, robots must use visual and language understanding, navigation, and manipulation capabilities. Existing datasets do not integrate all these aspects, restricting their efficacy as benchmarks. To address this gap, we present the Language, Navigation, Manipulation, Perception (LaNMP, pronounced Lamp) dataset and demonstrate the benefits of integrating these four capabilities and various modalities. LaNMP comprises 574 trajectories across eight simulated and real-world environments for long-horizon room-to-room pick-and-place tasks specified by natural language. Every trajectory consists of over 20 attributes, including RGB-D images, segmentations, and the poses of the robot body, end-effector, and grasped objects. We fine-tuned and tested two models in simulation, and evaluated a third on a physical robot, to demonstrate the benchmark's applicability in development and evaluation, as well as making models more sample efficient. The models performed suboptimally compared to humans; however, showed promise in increasing model sample efficiency, indicating significant room for developing more sample efficient multimodal mobile manipulation models using our benchmark.