Property purchase, buying right of way, special right/co-owner?

You have to ask the network operators how far they will lay your connection to the property, and then you need to know how many meters it is from the transfer point to the house. From that, the estimated costs can be determined.

As you have already noticed, choosing the rear property makes the development more expensive, but this is independent of whether you have a right of way or buy the path. I would always prefer the purchase if it is within reasonable limits.