Remote turn on is always blue. That's the EIA standard for all head units. I don't know why there would be an orange remote line, unless the installers used some generic wiring for it. To be safe, just check the amps in the back. If the remote line taped into them on the remote is orange, then use it. If not, run your own right off the head unit. As for the RCA pre-out, you can just run one single RCA if your amp is bridged mono.