Problem with two wireless routers in a network

My son has connected two wireless routers and other equipment in a network which functions properly in most respects but not all. I am trying to see if I can (with the help of others on this forum) correct remaining problems. Let me first explain the current set-up.

There is a Netgear wireless router which is connected to a cable modem for internet purposes. My son connects a notebook computer to this router wirelessly and it works fine.

He has then connected a lan port on the Netgear router to the Wan port on a Linksys wireless router. The Linksys is located in a separate part of his home where he and his wife have a small office for a business they run. The Linksys was set-up as part of a Vonage VOIP. The four lan ports on the Linksys router are connected to two PCS, a Netgear NAS device and an HP Multifunction network printer. Both computers are able to connect to the internet, the NAS device and the printer. If my son connects to the Linksys wireless router with his notebook computer he is able to browse the internet, use the printer and the NAS device. When he is connected to the Netgear he cannot print or use the NAS device.

The problem is that the Linksys does not provide good wireless connectivity throughout their home so he currently connects to the Netgear except when he wants to print something and then has to move closer to the Linksys router and connect to it so he can print. I recognize that he could probably solve the problem by adding additional range extenders to the Linksys wireless router and then simply turn off the wireless capability on the Netgear.

I would think however that there should be a way to allow him to be connected to the Netgear and also print and have access to the NAS without buying additional equipment.

It is this solution for which I am seeking the help of this forum. I am far from an expert with computers or networks and my son knows even less..if that is possible