D&H road is 161.1 and the last I checked CP was still on that (i.e., last year's train).
The train will probably lay-over during the day on Saturday in Kenwood Yard in Albany: last year it was holding at the northbound home signal and departed at about 5:30 p.m., all lit-up. This year the home signals have been moved south to the north end of the yard, so it will probably sit in the yard at the north end.
Last year I chased the train to Mechanicville with no problem, arriving in Mechanicville ahead of the train. As you will be passing Kenwood on the way from the City to Saratoga you could see the train several times, unless you really want to be in Saratoga for four hours.
There is a substantial yard in Saratoga, so it would be a good bet (better than the nearby ponies) that it will spend the night there.