Camping at the Hash House site on the nights of Friday 24 August, Saturday 25 August and Sunday 26 August is included in your entry fee.
If you are looking for a place to stay nearby before or after the event, the nearest towns with motel-style accommodation are Goomeri (35 mins), Nanango (45 mins), Kingaroy (1hr) and Gympie (1hr 15 mins). For those people coming from Brisbane and not needing to visit the event area or Hash House before the event, Kilcoy is also a good accommodation option. It has a full range of accommodation and is about a 1hr 15 min drive from the Hash House via Jimna. Try this link on Booking.com for ideas.
The Visit Gympie Region website has some excellent resources for planning and booking your itinerary.