Going from TTL to RS485 is made simple by this prototyping friendly module. On one side of the board are the TTL IOs, and on the other are the RS485. At the core is a MAX485 which is powered by 5V. (google Max485 RS485 Module)

Complete HMI display with touchscreen. This screen can be serially controlled via an UART port. It also has GPIO outputs that can be controlled via the Nextion software. The graphical interface of this module can also be programmed via an SD card or via the UART connection.
Design your own screen interface with touchscreen in the Nextion software. For examples and library's see this Github.