BTW how will I set the time on this unit? or is that not one of it's functions?
Don't worry about time stamp unless the repeater is connected to a computer to log usage... and it didn't sound like that's what you will be doing. I have operated on a dozen GMRS repeaters over the years and none of them had internal ID or a time stamp. As I mentioned, it is the responsibility of each USER to properly ID themselves at the end of their traffic sessions. If it is set up OK from the seller, all you need is some high quality low loss UHF cable (Andrew Hardline is what many use as well as short runs of RG213)... and some way to fine tune the duplexer, and it should be good to go. You have a ham callsign, so check with your colleagues on 440 to see if someone is up to speed on that particular system. They may even have some mic info for you or at least a wiring diagram of the mic connector so you can get something brewed up yourself.
P/S - Add on: This company was a servicing dealer for that type of repeater. If all else fails, call their service department to see if they have MIC info for you...
2520 Marsh Lane
Carrollton, TX 75006