Spec out large warehouse with 4 data rooms

I am the sys admin for a company and we are in the process of building a large (200k sq/ft) warehouse. I am not a network admin but have been able to spec out and set up smaller sites in the past. This site is going to require 4 data rooms to cover the whole building. In addition it is remote to our main office so any on site visits would require airtravel. I am trying to plan this site to be as stable as possible and provide as much redundancy as possible. What are some best practices to use when building out such a large site? We are planning for HA pair firewalls but beyond that we don't have anything else set in stone.