Static Route or VLAN

Hi Everyone, longtime lurker, first time poster!
I have a situation where I’ve forgotten my Networking Classes knowledge some 20 years back.
I have my main router at 192.168.0.1
I have four sub routers at:
192.168.0.11 Subnet 192.168.1.1
192.168.0.12 Subnet 192.168.2.1
192.168.013 Subnet 192.168.3.1
192.168.0.14 Subnet 192.168.4.1
I have a programmer writing monitoring software for devices in each subnet. What is the best way to allow him to have access to those subnets? Static Routes, VLANS, something else?

Michael
“I Drank What?” – Socrates