Actually, the 100-Mile "Wilderness" is crossed by logging roads every 20 miles or so, and there are two resupply options.
One is to have a drop made about half way through, run through Shaw's boarding house. This may not still be offerred since Mr. Shaw passsed away last year, but it might still be available with other workers at the boarding house making the preplanned runs.
The other is White House Landing, a hunting lodge about 68 miles into the Wilderness. You walk a logging road about 3/4 of a mile east to a foot trail, head another 1/3 mile up it to the boat landing, and blow an air horn and a boat comes across to get you. Their food prices are steep, but if you want to reduce the size of your food bag, it IS an option.
But for truly remote terrain with minimal vehicle access, the Smokies are technically more remote, with the longest stretch of trail with no vehicle access (38 miles). I knew 4 hikers on my 99 thru-hike who were day-hiking the 100-mile wilderness with two cars shuttling them.
If you truly want to get away from crowds, go just outside the Smokies into the Pisqah National Forest on the North Carolina side. Here you get relatively few hikers and TOUGH climbing trails in a true wilderness wilderness setting.