The large diagonal line visible in most of the pictures is the path of the main water line that connects Lake Rockwell (Akron's main water supply) to the city of Akron. I was told by my history teacher at Roosevelt (Bruce Dzeda) that the school was able to use the water from that line to water the athletic fields for free in lieu of future problems that might occur with the line needing serviced. I haven't been able to verify that, but I do know up until the completion of the Kent Water Treatment Plant and wells along SR 261 in the mid 1970s, Kent did get water from Akron to supplement their own supply. Now, I don't believe they do, outside of possibly having an emergency hookup. Another point to make is that the campus has obviously expanded. Initially, it was 31 acres. Over time, adjacent parcels were added. The scope of the original campus is pretty clear in the 1959, 1964, and 1966 pictures. The most recent additions to the campus itself were done in the 1990s for the construction of Stanton Middle School. Best I could gather on the Portage County Auditor's website, the entire campus is now around 88 acres. The county doesn't consolidate the parcels on the map, so that total comes from adding up the 18 or so contiguous parcels owned by the Kent City Schools (which is listed by several variant names).
The Portage County Auditor's website is a great tool for history, but obviously that wasn't its main purpose. It's mainly to provide a fairly accurate map of all properties in the county, plus it includes data on virtually all of them, like how much they are worth, how much each property is assessed in property taxes, who owns them, what school district they're in, and even has sketches of buildings on the property (showing outside measurements). There is a search tool by address or last name (or even parcel number), but even better is the map tool which allows you to click on a parcel and it will tell you who owns it and have a link to the details available. I've found it very convenient in discussions that have involved property values and taxes as well as just being a way to be informed about who really owns a particular piece of land or building. Check it out if you live in Portage County. It can be found at www.portagecountyauditor.org.