-- Last Updated: Oct-05-12 10:03 AM EST --
People don't usually ask if a something is "practical" or not. That's because what's practical for one person is not practical for another.
I know quite a few paddlers who can put in 40 mile during the daylight hours. After all, if you can paddle consistently at 4 mph for 10 hours, that covers it! 4 mph on flat water isn't all that hard to do for strong paddlers with good technique on a fast boat. (I was on a trip where the complain being the group going too slowly at "only" 3 knots!)
So, why complicate matters by paddling at night? If you can maintain 4mph, you get to see the scenery along the bank, and sleep relaxingly when it gets dark. But if you can't maintain that speed, you're better off just take a few lesson & practice some more. And maybe get a faster boat.
I'm a better cyclist than I'm a kayaker. I do 100 miles in about 6-7 hrs and do the same the next day. But every so often, I would see "athletic" newbie on a hybrid spending 12 hrs struggling to finish 100 mile. They insist it's an "achievement" just to prove they "can do it". Well, all it proves is their ignorance. Because with a little training and more appropriate equipment, it's just a casual day!
So, go out and paddle 10 hrs and see how many miles you cover and whether you can get up the next morning and do it again. You don't need to ask, you'll see for yourself whether it's practical or not, for you!