The Super Collider was never finished due to budget cuts. About 14 miles were completed out of approximately 54 miles. The funds were diverted to the International Space Station (ISS).
The Super Collider was a real project in Texas from which Congress pulled funding in October of 1993. The building shown in the establishing shots in several episodes for the scenes with Dr Sturgis is the actual Superconducting Super Collider (SSC) building near Waxahachie, Texas, built in the mid-1980s, now abandoned.
John's letter to Connie is addressed to her address in the fictional town of Medford, Texas, with a ZIP code of 75922. This code is unassigned, but its first three digits would place Medford near the real town of Lufkin, Texas, 75901.
When Connie is listening to the radio, the weather report states that it will be 97°F, but at the university, only a 1 hour drive away from Medford, Mary is wearing the sweatshirt, that Sam bought for her, when she attends the bbq, which started at 13:00.