Objects can be hidden in locations where no one would look, these locations can be used as a conduit to the future

An ancient laboratory is to be found in the cellar

A mirror can be set up for entrance from the future. Only the amount of time between now and the counterpoint needs to be 'set

In the attic, in 1910, is a brain in a jar (as a matter of speaking), which can be hooked up to the machine in 1960.