Is there any special etiquette or "good things to know" for hiking a section of the Appalachian Trail (AT) during AT, or peak, season (for that section)?
I think what you are trying to get at is the proper etiquette for hiking on the AT during peak season, when the most hikers and backpackers are on the trail. Exactly when peak season is, and how many people you will see at peak season really depends on where you are on the trail. Various places will have different number of Thru-hikers, section-hikers, weekend backpackers, and day hikers.
My experience is mostly hiking the parts of the AT in Virginia and North Carolina. We see Northbounders and Southbounders cross as well as lots of day and weekend activity.
Etiquette I would break into things you really need to be aware of and just nice things to do. As a day hiker I would say to be very aware of the following:
- Step off the trail and allow backpackers access to the trail and passing each other. Backpackers usually give the uphill hiker "right of way" but day hikers have less weight and should always accommodate the backpackers.
- Be especially careful of trash that you may leave behind, as the number of hikers increases the importance of this increases
- Be especially careful about staying on the trail, including switchbacks. As numbers of hikers increase and it rains erosion can get worse.
As for things I find that are good to do, and I would consider good etiquette are:
- I bring additional materials like water, first aid, and fresh snacks. If I run into a thru-hiker or section hiker I give any additional materials I have to them.
- I also bring a couple of spare trash bags that I keep in my day pack to pick up some of the trash left by other hikers, again, peak season this becomes even more important.
Also, you mention hiking, but there is one important etiquette item I would want to add for backpackers during peak season for thru-hikers. Bring your own tent/tarp, even if you expect to stay near a shelter. If more hikers end at a shelter than the shelter can hold I always stay in my own tent to make sure thru-hikers get the shelter.
In peak season (late spring/summer) most trail etiquette on the AT relates to thru-hikers, but not all of it, and generally is about the same on the whole trail. Thru-hikers are of course those who are continuously hiking the entirety of the Appalachian Trail, north or southbound. This information is essentially entirely based on my experience on the AT and hiking in general for many years.
In short, simply be polite and respect others and the wilderness in which you find yourself. Leave things better than you find them.
In more detail, general etiquette is the following:
Yield the trail to an hiker traveling uphill if you are a headed downhill, day-hikers or backpackers either one.
Yield the trail to thru-hikers (usually quite evident which are thru-hikers and which aren't) if you are not one.
Let thru-hikers have priority in shelters or other campsites.
If you are sharing a shelter or campsite with a thru-hiker, be respectful and quiet. Many thru-hikers go to sleep relatively early so they can cover more ground the next day.
When hanging a bear bag, do it away from camp and from the trail if possible.
Follow Leave No Trace principles
Pass on important and pertinent information to hikers heading the way you just came, such as bad trail conditions, swarms of stinging insects, presence of a snake, other dangers,...you get the idea. Or tell thru-hikers about locations of "trail magic" (See below.)
Say hello! Unless it's a particularly busy area where you can't greet everyone, it's very common to greet other hikers as you pass each other. Some people will not greet you, but that seems to usually be the exception. This applies to most trails in my opinion.
Strike up a conversation with a thru-hiker. Often-times they are hiking solo and welcome some good conversation, and are usually interesting people too. There are some however that just want to be left alone. Respect that as well.
When driving to/from the trailhead, give a ride to a thru-hiker who might be trying to get to the nearest town, post-office, hostel, outfitter, etc.
This is less etiquette and more hospitality: Leave "trail magic" for thru-hikers. Trail magic is essentially just a cache of food or drinks (especially cold) that are left along the trail to which thru-hikers can just help themselves. Usually people from the surrounding community do this, but that doesn't mean section hikers or day-hikers can't leave some too.
If you aren't a thru-hiker, don't take the "trail magic".
For information on specific sections I recommend a guidebook for the particular section being hiked. There are several available. The Appalachian Trail Conservancy offers these guidebooks which are quite detailed, and may be found in many outdoors stores near the AT as well as online. Another kind with a digital version is offered here from the ALDHA. Downloads are free for ALDHA members only. It seems you'll have to pay for pretty much any type of guide, but it's worth it usually. While the primary purpose of these guidebooks is mostly to educate about the trail and the area, you could likely infer specific etiquette from that information if needed.
And finally, go to a local (not a chain) outfitter/outdoors store in the area you're visiting. They will likely have good information and be up-to-date on the local trails. Also many regions have specific hiking clubs and associations that maintain websites with a good amount of information and people to contact.