My players want a campaign out of my one-shot! HELP!

So a while back I had the idea for a one-shot based around the three little pigs (still serious) where the big bad wolf was some kind of demonic lycanthrope with a breath weapon. When some of the group couldn’t make it, they asked to do a sort of session zero for my one shot with an encounter. It went well! …for once in my life, maybe a little too well. Now they’re interested in a full campaign based around what they’ve seen so far! The crazy part is I don’t think they’ve figured out what it’s based on yet! So, I’m looking for ideas.

So far, after 100 years of no werewolves, two people transformed into hybrids at the tavern the party was meeting a contact at. A halfling (little pig) spoke of running into a big one last night at his home and is interested in hiring the party. They checked the rooms of the ones that thrned and found a map of around where the halfling (Al Bacon) lives, so they are going there next session first.

Along the way, they’ll run into a Tiefling girl named Red going to her grandma’s house. When she gets there, she’ll notice parts of her body aren’t quite right. Needless to say it’s another wolf, but this one seems to be able to shape-shift to resemble other people! The party can find grandma’s regurgitated body from the Big Bad Wolf earlier, as well as a note revealing the grandma’s mother was a blood hunter who helped make a deal with Malar the beast god to get rid of the werewolves for 100 years.

I’m assuming after that, they’ll go to the three halfling’s houses to make plans to fight the Big Bad Wolf when it returns. We’ll see how they strategize and what damage it can do to the infrastructure with its breath weapon.

That’s the short version of what I have planned. So, where should I go from there? Do I try to make it last longer? Do I make more werewolves? Do I go with the fairy tale theme? Do I call it quits after TBBW?