The Dry River area is wilderness area and has a pretty consistent reputation of poorly marked trails. The Dry River Cut off seems to give a lot of folks troubles staying on trail down near the Dry River trail. intersection as the trail seems to disappear on occasion. Davis Path has a reputation of lots of blowdowns. In general the Dry River Area wilderness has far worse reputation for difficult trail conditions than the Pemi. The actual lower Dry River Trail was severely washed out several years ago and it was never repaired. There are bypasses of the worst washouts but it has made it difficult to access which means fewer hours spent keeping trails open.
The main trails in the Pemi are old railroad grades and very beat down so they are not hard to find or follow. The problem is like the old logging railroads, all trails lead to the Lincoln Wood Parking lot which means a hitch or road walk to Lincoln. There is an option to bushwhack up Lincoln Slide but you are better off just sticking to the AT.
There are not great options to skip the presidential traverse. You can skip the carters and wildcats by taking the Pine Mountain Trail out of Gorham (the trailhead is difficult to find) which eventually turns unto the Pine Link trail that goes directly up Madison.
Linked are the official WMNF rules for backcountry camping.
https://www.fs.usda.gov/Internet/FSE_DOCUMENTS/stelprdb5363715.pdf It was either intentionally or accidentally composed to confuse Leave No Trace
recommendations (page2) with WMNF
regulations (Page 3). Just because the rules say you can does not mean that the terrain and vegetation will allow you to find a site. Generally if you camp at lower elevations on flatter terrain you have far more likely opportunity to find a spot under hardwoods or mature softwoods than up higher where there is a lot more dense spruce/fir scrub.
These days various trail aps list legal and not so legal sites along the AT. The only real tough spot is near Mt Washington and Lake of Clouds hut. There is no great alternative to a hut stay or the Dungeon under the hut which lives up to its name. Most folks stay at the RMC camps or the Perch and then head south to Nauman near Mizpah. The caretakers at the shelters will always pack folks in somehow using overflow spots and most huts have places just outside the 1/4 mile RUA for thruhikers. One dangerous illegal site that is nevertheless used by some thruhikers and other backpackers is Sphinx col. If there is bad weather anywhere in the whites, Sphinx Col is going to be right in the middle of it and storms tend to funnel right through it.
Note there is no easy way out of the Great Gulf, all three options, Six Husbands, Sphinx and Great Gulf are very steep, Sphinx being the least bad of the three.
