>>2060828depends if you want campsites along the trail or where you can just park and camp there, but with trails nearby, less crowded would be gandy dispersed camping area, i dunno if there are campsites along those trails (elza, big run) but there are big parking spots where you can access a buncha different medium distance loops (1000-1500 ft elevation gain maybe) along gandy creek.
you can make seneca creek into a loop with lumberjack or allegheny trails. otter creek wilderness a loop is going to run you a lot more distance and elevation gain, I would do that out and back
are you going on a weekend or weekday?
ANF is entirely worth it, but I would wait a couple weeks for it to green up a bit.
(pic related is ANF)
and there's this youtube channel which has videos of a couple different dispersed camping areas:
https://youtu.be/OSgSkzK-WnY 