Rural areas are the last regions aiming at getting access to broadband services due to the high investments and limited revenues. However, new architectures such as Hybrid Passive Optical Network (HPON) allow interconnecting fixed users and Base Stations with the same infrastructure. This paper looks into the advantages of the HPON joint planning with respect to an independent planning of mobile backhaul and fixed users. The recently proposed HPON architecture could offer more bandwidth to the base stations (10Gbps) and less bandwidth to residential users (300-500Mbps). The results show the cost reduction of supporting joint planning in two real rural areas and analyze the impact of the number of base stations and their inter BS distance (i.e. different cell sizes) on the savings.