Vern asks the group, including Gordie, if they want to see a dead body after overhearing his brother talking about how he and his friend found one.

At this point, I think the group including Gordie, just wanted to try and be a hero and possibly make the news since the body might be of a missing kid.

His best friend Chris, who is also their group leader and the wisest of the group, understands Gordie better than anybody.

Gordie has his brother's hat who has recently died

Gordie is with Chris, Vern, and, Teddy. All in the same friend group going to find the body.

When they leave Castle Rock and go towards the body in the start of a long walk.

Maybe his brother. His brother recently died, and we were shown flashbacks about him during the journey, so he was definitely thinking about him.

The junkyard owner and dog, not much money for food, the train while they were on the train tracks, and the leeches in the water are all challenges to Gordie.

In flashbacks, Gordie thinks about how his family made him the “ invisible son”  after his brother died and how his Dad might have wanted Gordie to die instead.

Gordie thinks his father doesn't love him as he knows his parents have been silent to him since his brother's death.

When traveling through the final parts of the journey to the body,  the group has to travel through some water and everybody gets leeches on their body. One of the leeches was on a specific part of the body that made Gordie faint.

Goride has a special bond with Chris more than the other guys, as he feels like Chris understands him more as Chris's father doesn't like him either.

 I think it's definitely possible Goride will try to make amends with his father after they find the body, but we don't see.

Gordie and his friends find the body, Ace and his gang are there as well and they want the body instead. Ace says either they leave and they get the body or they get beat up and they still get the body.

Gordie threatens them with the gun Chris brought and they get the body to themselves.

Gordie realizes they're not heroes for finding the body and decides to make finding the body easier and in plain sight so someone else finds the body.

I think he's trying to escape his thoughts about his family, as ever since his brother died, they have been paying much attention to him, and he thinks they hate him.

Gordie and his group of friends return to Castle Rock and go their ways.

Yes, as we get a flash forward to when Gordie is older and he is all settled with kids, successfull and is now talking about the time when they found the body. A type of guy I do not think he could have been with the same mindset he had at 12.

Gordie is writing a story about this journey many years later after he hears Chris was killed in a diner. I think telling the story will give everything resolved if it wasn't already.