On most vehicles, there are a number of gaskets under the dash on the drivers side. The brake pedal, the shift lever from steering column shifting, some even have unused gaskets. Sometimes there is enough space beside the electrical wire feed through gaskets.
Just make sure that when you make the hole, that you don't damage any wiring that may be close. In some cases, it may be required to use a drill because of the type of material and thickness of the gasket.