As mentioned before, Reaper is an extremely powerful tool for programming when dealing with audio/video playback. One of the more powerful features is its integration and playback using various types of timecode. In addition to being able to route a pre-made timecode track as needed, either through your sound card or USB audio interface, Reaper has the ability to generate its own time code and output that. This is useful if you need to change the format of the time code or don't have it to begin with.
In order to add your own generator, start by creating a new track under the audio you wish to use (Track>Insert New Track). Then while in that track select the insert SMPTE LTC/MTC Timecode Generator from the menu (Insert>SMPTE LTC/MTC Timecode Generator). Following this you'll want to position and drag to length the generator item. Once the item is inserted and sized, right click to adjust the properties.
From the window you can decide the type or source (LTC/MTC) and when the generator is supposed to start at.
After selecting the options for the track you need to route it somewhere for it to actually get out to your console/device. Before doing this you'll need to setup the output options under Preferences> Audio or Midi devices. By clicking on the routing button down in the mixer settings you'll get options how to route the track. (See picture)
Another possible feature of Reaper is the ability to control playback itself through an external timecode source. By right clicking on the play button you get an external timecode synchronization popup. Form here you can set Reaper to begin playback from an external source and chose the flavor. You can also create offsets here as well. This makes it possible to use Reaper as a makeshift timecode translator from LTC>MTC or in reverse as needed when you don't have hardware like a Horita on hand.