His mother was an artsy-craftsy sort, and she wanted to make sure that we weren't getting into trouble, so she actually created Trek-themed projects for us to do. We made plywood "control panels" for our "ship" - including a "transporter console" with sliding levers (wide beads on strings) - which Mark's father mounted on the walls of the shack. We made uniforms out of appropriately colored tee-shirts, which his mother helped us draw insignias on with fabric paints, and we made papier-mâché planets, which we suspended from the ceiling of our clubhouse/starship with fishing line.
But mostly, we role-played being crew members of the Enterprise, and explored the alien cornfields and woods on the Usher property. We kept in touch with the Mego Star Trek Communicators, which were - as the advertising proudly exclaimed, "real, working walkie-talkies!" But unlike the other walkie-talkies we had as kids, these had flip-up lids, just like the ones on TV. Of course, they were considerably larger than their television counterparts, colored blue, and had telescoping antennae - but they worked.
If you didn't wander too far apart, anyway.
For those keeping score, the coolest 70s toy ever was the Mattel Space: 1999 Eagle Transporter. The second-coolest toy of the Space: 1970 era was Kenner's 18" Alien. And the third was Kenner's Bionic Bigfoot from The Six Million Dollar Man.