Ahh, must be the same Eman I answered on LinkedIn.
Arapiles and Grampians are close together. You could stay somewhere called Horsham which is sort of between the two but I have no idea what the accomodation would be like. We nearly always camp. The main tourist centre in the Grampians is Halls Gap. Loads of accomodation there including hostel style accomodation.
Fly into Melbourne for these. Mt Buffalo is off in a different direction (from Melbourne). All are within around 4 - 5 hours driving.