I have an excel spreadsheet set up. Each line item list the date, destination(s), # of nights spent, and miles traveled. I don't worry about exact mileage. I use google maps by entering the start point, intermediate point(s), and end point to get a resonable mileage number to plug in. When I do things like buy new tires or pack bearings, I enter a new line item at that point in time.
Then at the bottom I have summation cells to keep a running total of miles traveled, total nights spent, miles since last bearing pack, miles on current tires, etc.
Simple and easy to do. I update it when I return home. And I do not have to worry about remembering to read the odometer each time.
