Mowing systems include a mower and, optionally, a remote control unit such as a handheld unit, between which may be 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 monitoring a tilt angle of the mower, and defining or executing different system responses as a function of different first and second conditions that relate to the tilt angle. Another aspect relates to automatic adjustment of a speed setting of the mower's drive system as a function of a power takeoff (PTO) unit of the mower.