I'm surprised that this is the first I've heard of wiring a remote switch.
How about this - I've mounted the sender in a plastic utility box behind the grill. Its sealed from the weather and plastic doesn't compromise the RF. If you don't back up the street (or alley) to your garage, you should get a few more yards range since there is less metal to deflect the signal.

Jim Weiss
Three bricks, want more....