How soon before train departure do you need to arrive at station? Is there security check of baggage causing delay of boarding? Do they have visitor parking so you can see family member boarding train?

Depending on which train service you'll be using. You can arrive 10 minutes before, get a ticket and navigate your way to the track. No baggage checks. Parking is available but not free.

You can actually arrive 2 to 5 minutes before it's time for the train to leave and you would still be fine as long as you have bought your ticket beforehand unless you want to pay for tickets on the train for the higher fee, no security check per say but there are police that walk around with dogs at any time or on any given day in the front just across from the taxis you can actually Park and let a family member out and you can see them board the train but it's not for a long period of 5 minutes or so to the maximum