My initial response was:
It really depends.
How good condition are you in?
How good are you at keeping your load light?
Then I looked at the link. First thing to note is you've shown it following I-87, which is neither pleasant nor legal for bicycling. So I moved your start point to Plattsburgh and the end point to Saratoga Springs. And then I selected the little bicycle icon, to get bicycling routing.
This section is pretty much entirely within Adirondack State Park. The roads are generally not super steep, and the hills are not super long. That is, they are not steep by Virginia/Kentucky standards, they are not long by Rocky Mountain standards. You will be climbing some of them for close to a half hour, and then going down the other side in minutes.
Google Maps bicycling offered two alternate routes, slightly longer, but they look flatter. I would tend to opt for the flatter ones. One crosses to Vermont near the start, and then pretty much follows the shore of Lake Champlain. It looks flattest.
To get a sense of the real gradients involved, consider using a site such as mapmyride.com for that section to see how steep the steepest part is.
My conclusion is that if you stick to NY-9 (which is parallel to 87), you should be able to ride 40 mi/60 km per day if you're in reasonable condition. If you switch to the Vermont side, you should be able to ride 80-100 km per day, depending on load, and your physical condition. According to MapMyRide, there are no climbs greater than 1% (there may be very short climbs steeper than that), and no downhills steeper than 3%.