Can I load my Remington #2 rolling block hot enough to harvest a whitetail deer?

Am guessing you are talking of the 38-40 wcf. I freely admit that my experience is limited to the fact that I have a low wall in that caliber, a box of factory ammo and reloading components except for bullets. I do however have experience with its big brother the 44-40. Factory smokeless loads are pretty mild due to the vairety of rifles it was chambered in. Reloads will do you much better. If you can, load some up with Black Powder and a cast leas bullet. You may be quite surprised at the performance over what the factory has put out. If you do limit your range to about 50 yards or so and place your shot well it will kill a white tail with out any problems. 
If you do a web search you will find a good bit of info on loading the 38-40, mostly for handguns but will work equally well in a rifle.
Sam