basic rules of thumb..
YLHR NOTHING = INTER, INTER = TEMPO, TEMPO = ALTN. VFR YCKN is probably the only alternate worth using unless you can reach YHID. YCOE will usually recipricate the WX at YLHR without the localised bad weather YLHR is famous for. YBWP is also ok HOWEVER if the weather is really that bad you probably wont make it over the hills to get to WP, especially during the wet.
Going up the coast is quite scenic. Depending on your fair weather experience I would try to go prior to the commencement of the wet season otherwise it can catch an inexperienced pilot out. The Area is also remote so be sure to carry survival gear just incase.
As bullwinkle said take plenty of fuel, dont be pressured by time and enjoy a very exciting part of Australia. Good luck and feel free to shoot any questions.