Short answers, pulled from the story.
The Apollo Applications Program was created in 1966 by NASA headquarters to develop science-based human spaceflight missions using hardware built for Project Apollo. It was intended to give the roughly 400,000 Apollo workers continued employment after the first lunar landing.
Fiscal Year 1967 allocated just $80 million to the Apollo Applications Program, compared to NASA's preliminary estimate of $450 million needed for that year alone. The Johnson Administration declined to support the full program in order to remain within a $100 billion overall budget.
The most advanced concept, LESA (Lunar Exploration System for Apollo), envisioned a permanent base powered by a nuclear reactor, with crews of up to six people staying for 180 days at a time and surface payloads of 25,000 kilograms. Earlier phases planned two-person crews in Apollo-derived shelters staying up to 200 days.
The wet workshop concept called for a Saturn S-IVB upper stage to be launched with fuel, then have its remaining propellant vented to space after use, after which a crew would enter the empty tanks as living quarters. When Saturn V production ended, NASA shifted to a dry workshop approach, outfitting the S-IVB on the ground before launch.
After NASA's 1969 budget was cut, the Apollo Applications Program's separate missions were consolidated into the Skylab space station. The Apollo Telescope Mission was absorbed and renamed the Apollo Telescope Mount. Skylab's first crewed mission launched on the 25th of May 1973, and the third crew completed an 84-day stay.
The Grand Tour was transferred out of the Apollo Applications Program to the Mariner program as Mariner Jupiter-Saturn, and was later separated into the Voyager program. Two probes launched in 1977 on Titan IIIE rockets, and Voyager 2 completed the full outer planet Grand Tour in 1989.