The Long Trail is in many ways, similiar to other long distance trails in the east. So, what ever gear you would bring along for that trail you will probably want on the LT.
Sunscreen? Probably not. Mostly under tree cover
Hiking poles? Probably yes if you use them. There are lots of ups and downs that can be hard on the knees.
Rain pants? Well, in my case, yes, because Frogg Toggs will be the only long pants that I take along in mid summer.
Sweater vs fleece jacket? Evenings and early morning can be cool. I’d probably take along a fleece shirt that I have. So, bring along something that you are comfortable with.
Sandals or low boots? Frankly, my preference is boots. Sandals don’t have enough protection and support for me. The trail is rocky, just like most trails in the Northeast.
Peaks