There is water source at pos V via Cemoro Sewu (Jolotundho pos). And, there is a food stall right 200 meters below the peak. So it's OK to "tek tok" (go up then down), whitout camping.
It's only need 5-6 hours to summit via Cemoro Sewu. And it's only need 2.5-3.5 hours to down via Cemoro Sewu.