Originally Posted by infaddict
Thanks for the response. Can you expand a little on what you mean? I'm not sure you mean. How will a sampler help me load up projects or play tracks inside Reaper?
A sampler plays audio files, which are typically triggered by MIDI notes. And a backing track is just an audio file. So it's easy enough to load all the backing tracks into a sampler, and map every audio file to a separate MIDI key (& channel).
Since a sampler can also be implemented as a virtual instrument (e.g. a VSTi plugin), you can use it within REAPER like you would use any other plugin instrument, and make a project that loads the sampler, including all the backing tracks mapped to MIDI keys as a 'preset' in that sampler.
(If you're not familiar with samplers, perhaps have a look at plugins such as NI Kontakt, to name just one popular example. REAPER also includes a very basic sampler: ReaSamplOmatic 5000.)