Another easy week-end trek from Jakarta is around the Jatiluhur lake, next to Purwakarta. Purwakarta is a town on the main Jakarta Bandung highway, meaning that any bus going to Bandung may drop you there. Stop at Plered, where the Jalan toll interesect with Jalan Raya, then ask to ojeks to bring you to Cisarua.
Both Bongkok and Parang are not volcanoes, but are included here as an exception, as they are pleasant summits, accessible from Jakarta.
From Cisarua, if you climb Bongkok first, you have to find the start of the trail, ask the locals, the Bongkok summit is easy to spot even from Jalan Toll, it s the only and highest rocky top around. First ask for some water, as there is no water up there, you will find a tap near the big mosque. Go on in the South East direction, and you have to climb to a bamboo forest marking a kind of pass, at 650m. At this point turn sharply right, and head North East, the trail is well marked but steep. At 950m, you reach the summit, immediately on your left. You can camp there with fantastic views on Jatiluhur.
To go to Parang, climb down Bongkok to Cisarua, then follow the road heading North during 1km, at the interesection, turn right for another km. At the entrance of the village, you will find a kind of kabupaten/Park office where you can get information [and water]. No need to pay anything here. Just follow the track going up to Parang, first head South West, then South for 90min, and you will reach the Parang Crest, the true summit [920m] on your right is not accessible, so just go to the grassy North Summit [900m sharp], which is pleasant and with views.Â
It s time to go down Parang again, and reach the road. Transport are scarce here, so hitchhike any car or truck passing by.
Have a nice trek