16 miles is not too long, but 2000 feet of climbing is quite a bit for a commute. Not impossible, but doing it every day could be a challenge. I've always felt a bike commute of 16-20 miles is perfect. Anything shorter than 12 miles- well it takes me 10 miles just to warm up.... Longer than 20 miles and its going to eat too much time out of your day. A 16 mile rolling commute will take about an hour at moderate pace, a 16 mile flat commute could be done in well under an hour.

My current commute is 16 miles each way and it includes a tough climb, but only 500 feet vertical. I find its toughest on Monday morning or the morning after a hard training ride the night before. Its hard to do a recovery ride up a a big hill!

If you can cut out the climb with the 19 miler, then you're in business!