A mobile storage unit system includes a vehicle guide arrangement that navigates a forklift or other vehicle along aisles formed between mobile storage units. The vehicle guide arrangement allows an operator to identify the aisle containing a desired loading or unloading point and the guide arrangement defines a path of travel for the vehicle along that aisle to ensure that the vehicle has sufficient room to perform the loading and unloading functions. The mobile storage unit system may also include one or more perceptible indicators, such as lamps, that provide the operator a signal when an aisle is fully open and ready to receive the vehicle. A corresponding signal may also be provided to the vehicle guide arrangement so that the vehicle is not navigated along an aisle until the aisle is fully open. This ensures that the vehicle has the space needed to maneuver during the loading and unloading process.