Guest houses in Fukuoka

I'm starting my Working Holiday next month and planned to stay in Fukuoka for a while (2-3 months) after traveling south.

I browsed some guest house sites, but most are focused on Tokyo and Osaka. Hostels like Khaosan probably aren't well-suited for longer stays.
At what sites can I find cheap accomodations and maybe part-time job offers if my plans don't go that well?

One option would be to check local temples in the area, as they often offer rooms for individuals on the compound for fairly cheap.

As for part-time work, there are probably few places online that advertise the need for part-time workers, so that is something you'd have to investigate when you arrive.

In regards to lodging, your cheapest bet would be something that is rather common among younger people: Go to an internet cafe that offers private booths and rent a booth for computer use for a few hours, and sleep in the booth for a few hours at a time.

This was something myself and others traveling with me through Japan practiced frequently. It is even better when you find a cafe with showers, and larger scale booths with a sofa.

I doubt temples and internet cafes are really suited for staying 2-3 months, but maybe an option for the first days.

I also have to register an ARC by then. Quite hard to do so with a cafe as accomodation, don't you think?