Regarding power, I assume it is the same principle like when discussing road access? So, you should ask the seller for help to find a solution with the neighbors in case your land is locked in and has no access to electricity yet?
In case of public road access, but no access to electricity yet: Probably, it is the easiest way to lay the power line along the road then, so that you do not have to ask neighbors for permission? But are village officers usually cooperative and allow that? Probably, the potential buyer has to carry the costs for installation of the power line along the road then. But is it also common that the government/village officers reject a request for a power line along the street if someone wants to obtain access to electricity by that?
Access to water is also to consider but, regarding negotiation with neighbors, probably a less problematic topic since in most cases you can drill for water - and in most areas it is also possible to have water delivered in case of road access.
For power, if there is a public road, PLN has no issues planting poles on it and connecting you. There may be a fee for this, if it is a long distance, although i'm not sure if it is official...lol.
Water, as you have surmised, can be drilled for, and most of Indonesia does this.