My daughter and SIL just bought a used '96 Jayco 1006 popup for their first camper. He called me asking some questions. We have a Class C so I couldn't help him much. His main question was about us...
Our Starcraft popup simply drained out the side of the camper onto the ground until I ran a pvc pipe from the drain to a 5 gal bucket with some sand in the bottom. I placed that behind the bumper under one of the slide out beds. All we had was a small fresh water tank.