I try to keep it very simple and make it less apt to open avenues for dickering.
Once the location is determined, the hours, the enhancements, etc, an all-encompassing price is given. If the event is outside my ordinary range of action, I figure (in my head ONLY) $75/hour travel labor and $1/mile, plus any meal costs and lodging expenses.
When the fee is quoted, they are told that the fee does include all travel expenses, all of them. They don't need to know what they are or how I calculated them. I will not accept any customer providing me with lodging. Burned twice being lodged in a fleabag bug infested dump and another 40 miles from the venue.
Providing customers with line-item billing and explanations leads to nothing but grief.