It depends on what you're into. Some people prefer to rent a van and just drive up the coast on their own, but that wasn't for me - for one, I was on my own and I didn't really want to commit to spending several months with someone haha, so I just wanted to meet lots of people and stay in hostels and everything.
Instead, I got a Greyhound bus pass. There are several different passes, for example one for 200 km, one for 500, etc. (or at least that's what it was like two years ago). I thought the bus pass was relatively cheap, considering how big Australia is and how far you actually drive. To put things into perspective: Byron Bay is considered to be close to Sydney - but it took 9 hours by bus I think. So it really is incredibly big
Always stay in hostels. Make sure to compare booking.com and HostelWorld prices, and on Hostelworld, never go to a hostel with an average rating of less than 7. Because those places really suck.
I stayed in the most incredible hostels, some with pools, palm trees, hammocks, free surf lessons, etc. and others with cockroaches, incredibly dirty kitchens, and covered holes in rooms to keep out the rats.
But don't let that discourage you - it's all part of the adventure, and those are the stories you'll tell later on haha
You can also apply for a working visa, but you can only get that once in your lifetime (except for special circumstances), so I wouldn't waste it on 8 weeks.
8 weeks is also a tough timeframe, because sometimes you can work in the hostel for a few hours a day, in exchange for free accommodation. But they usually require you to stay a couple weeks, so that wouldn't work.
I'd recommend you to definitely visit Byron Bay and hike to the lighthouse (on the way there there's an incredible beach, and if you go down to the beach and walk along the coast in the water, you get access to some really small "private" beaches). I also loved Airlie Beach, the Whitsundays are a must (I really recommend staying on the boat for a couple of nights, because those snorkelling trips are seriously insane. I also went diving in the Great Barrier Reef, but the snorkelling trips were somehow better. On the dive, I just saw a couple of fish and almost no corals, but on the snorkelling trips I saw schools of fish (literally hundreds), a Napoleon fish, glowing fish, and the most beautiful corals. I can't even describe how incredibly beautiful I was, but I can't attack pictures here unfortunately).
I also really recommend visiting the Josephine Falls. We rented a car to get there (just for a day), but it's so worth it. The falls basically have a natural slide because the rocks have become so smooth due to erosion.
I can also really recommend Magnetic Island! We hiked to Alma Bay and saw around ten baby sharks, which was so cool! Apparently the water around Magnetic Island is full of sharks haha
Also: you really have to go for a hike in Noosa National Park. It's the most beautiful thing ever. I met two girls in the hostel in Noosa and we got up at 5am and went for a hike. There were just a couple surfers in the water, and we spotted dolphins and whales. Noosa National Park also has "fairy pools" - they're natural pools created when there's low tide. We walked all the way to Alexandria Bay and it's so incredibly beautiful; like the pictures don't do it justice. We then stopped for breakfast at maybe 10am at Sunshine Beach and walked back to go for a swim in the fairy pools.
Also really recommend the Carlo Sand Blow!!
Also - I know that Fraser Island is really popular, but I would definitely recommend you to do the Whitsundays, if you can only do one or the other. Fraser Island is nice and all, but the only cool things is the Champagne Pool (which is similar to the fairy pools) and Eli Creek.
I know I've written way to much, but honestly I just think about that trip every single day and I miss it so much. When you're traveling, you just feel so free and time goes by so slowly in comparison to being at home. Really enjoy every minute of it, because once you're back it's gonna feel like you never even went.