I've never used liquid smoke before. When a recipe calls for bacon, or another smoked meat, I usually add Braggs Liquid Aminos to taste. It has a rich, smokey flavor which seems to work well.
You can usually find it in the spice aisle of a natural food store, or a well stocked regular grocery store. It comes in different sized bottles, and it's the consistency and color of soy sauce.
Hani