Alright, SoBo thru-hiker here, completed it last year. On the AT, whether you hit all the deadbeat jackasses will vary on if you go NoBo or SoBo. NoBo, you're going to be hitting swarms of people, hiking into the heat, dealing with pothead jackasses who are just there to party while hikers are trying to sleep and have constant "safety meetings." However, you're also hiking the trail the easiest way, and by the time you get to the Whites and Maine, you'll already be conditioned and good to go.
If you hike it SoBo like I did, you'll be hiking with the seasons (so the temp doesn't really change on you), with people who are pretty serious about hiking (because SoBo is the harder way to go), and there'll usually be just enough people so you're not completely isolated each night, but not so many people that you can't hike and be alone. HOWEVER, you're also starting with the hardest shit first. Once I got out of the White Mountains, I had a blast. I was already conditioned, I had no time limit (except my bank account), and I was with a small, tight-knit group. But getting to that point was hell, and I had to stop myself from packing it in and quitting no less than five times.
Overall, I had a great time. Hell, even the relief from reaching a town through that first few hundred miles of hell made the rest of it worthwhile.
As far as towns, outside of Maine, you'll be hitting a town at least once every two or three days, if you want to divert. Most are a bit of a hike/hitchhike off the trail, though, so it's really easy to just get extra food at one town and blow through two or three more without stopping if you need to make time. If you're a NoBo hitting Maine, you'll move to hitting a town every four or five days or so, up until the 100 mile wilderness. If you're a SoBo going through Maine, some sections you'll have to pack a week of food, even outside the 100 mile. Or at least I did, but I was a slow SoBo (a SlowBo, if you will).