Use the Start / Stop time to select the type of labour, i.e travel. this will make it easy to distinguish between travel time and labour time.
Have the start / stop timer automatically log individual date and start / stop, rather than one continuous running timer. This can be ideal where there is a significant break on one day - eg, you attend int he morning but need to leave site and go back to warehouse to collect parts etc. And ideal for multi day jobs, where you can easily see the time log for each day.