Okay, so... RTTE SPOILERS!
That woman queen girl from rtte( her names Mala or something, right )and her tribe will feature in this story!

Okay, fem!hiccup meets Toothless earlier than in the movie - without hurting him. She runs away with him( NO! NO ROMANTIC! )kills the red/ green death( without loosing limbs )and they end up going so far away that they meet Mala( or whatever her name is )and her tribe! She train with the warriors on the island, gets stronger, learns how to fight!
She stays there until the gang( who somehow ended up getting along with the dragons, and no, the don't know hiccup/ Hicca ended the war )have been through season 3 of rtte( without hiccup/ Hicca )and end up with Mala( seriously, what is her name!? )too. Just like the gang do in the series, you know, Viggo and all. They meet, blah blah blah... Adventure, blah...

I need more information for this to happen! :( idk, I find this to be an awesome idea xD

I'll writer more on this if i figure out more about blot and stuff!