Will there be a Season 2, and if so, how many seasons will there be in total?

The game has six seasons in total.

New seasons take quite a bit of time. Why is that?

I'm a solo developer and do pretty much everything on my own.
In Season 2, I acquired some help for the UI—especially the interactive phone.

Is there a way to follow the process of Summer's Gone - Season 2?

Yes.
I post bi-weekly development logs on various sites. There, I show previews and share other news.
A website is soon coming.