Mowing systems include a mower and a remote control unit such as a handheld unit, between which is provided 1- or 2-way communications. Components and features are included in the mower, the remote control unit, or both to enhance the safety, functionality, or user experience of the system's user/operator. One aspect relates to an enable switch on the remote control unit that requires activation within a specified time before activating a drive system or PTO unit. Another aspect relates to sharing diagnostic information between the mower and remote control unit and emitting user-detectable warnings in response to the shared information. Another aspect relates to reducing a danger level of the system, e.g. disabling the PTO unit or slowing a drive speed transform function, when a proximity between the mower and the remote control unit is too small. Another aspect relates to controlling operation of the mower based on tilt angles of both the mower and the remote control unit.