...when I worked for the co-op here, for a few years I was the guy in charge of managing "donations". So I have some resaonable idea of what might be involved in accepting this number of bikes in various condition and of various quality.
The junk bikes (of which there will be many) are a loser from the getgo. Scrap value will not cover your costs of transportation and the labor of disassembly (All the scrap places here want the metals sorted...so the alloy has to come off the steel, tires need to be pulled and trashed, etc, etc.)
The "high end" bikes that get seized by the campus cops only rarely go unclaimed. I used to turn down donations all the time if we did not have the space to handle them. It's just a sad fact of running a non profit staffed by volunteers that you can't always do large projects like this one.