If I have more than a day off at a time it is the only way that I hunt for big game anymore.
It is a physically demanding way to hunt, but I have found that if you are away from the roads a good 6 miles or more and off of the main trails at least a mile or two that you will see a lot more game. You will find that you can be back in the woods 10-15 miles and still see a lot of people on horseback if you are on a main trail.
For my longer trips lately I have been using a Crooked Horn High Country Extreme II backpack, but I have used plenty of others. Fit, balance, and weight are crucial. On a typical late season 10 day excursion including the weight of the pack itself, the rifle or bow, and a full water bladder I am carrying about 56-60 pounds. That is my max load, but for the majority of my hunting it is somewhere around 45-50 pounds everything included for a 10 day trip. Remember that your pack will get lighter every day as you consume food.
Backpack hunting is not for everyone, but I find it very rewarding and to be honest I prefer the solitude. If you have any questions or anything pm me, and I will do my best to answer.