Where is the best place to write my stories?

Most Sim-writers use either Wordpress or Tumblr. I use both. Either one could be easy enough, but there are a lot of options in Wordpress that could be overwhelming, and while Tumblr has comparable options, how to make the most of it can be difficult to figure out as it's not 100% intuitive to use. I think there are also a few Sim-writers that are on Blogger. You'd have to try them and see how it works for you. (I find them easy enough, but I'm also a programmer. ;) )

You could also just find an image host and post your stories in a thread here; a lot of writers also do this.

Good luck finding something that works for you, and happy Simming!