It sounds like you had quite the adventure in finding someplace to sleep in Northern Sinaloa... Your brave to have pressed on in the dark. I'm glad to hear you've made it to Mazatlan. Having spent the winter there years ago I'm confident your enjoying the weather and maybe even a swim in the warm pacific. There is no shortage of nice beaches around Mazatlan that are worth checking out for a lazy afternoon and if your lucky you may even find some nice waves.
Hopefully you can find the Funky Monkey Hostel. They have good visibility on google and appear to have a Facebook page. I'm sure if you ask around someone can point you in the right direction.
Good luck and have fun!