If you have 6 hours or a half day to spend in the town of Prestwick, there are several things to do that can fill up your time:
1. Visit the Prestwick Beach for a relaxing walk or picnic. It should take around 1-2 hours depending on how long you want to stay.
2. Visit The Robert Burns Birthplace Museum. This museum is dedicated to the poet Robert Burns and can take around 1-2 hours to explore.
3. Take a stroll through the Prestwick Promenade. This walk is extremely popular, as it has many places to take a quick break and enjoy the scenery. It should take around 1-2 hours to walk at a leisurely pace.
4. Visit the St. Nicholas Church. This is one of the oldest churches in Great Britain and can take around 30 minutes to an hour depending on how much of it you want to explore.
5. Explore Prestwick Main Street, which is lined with independent shops and restaurants. This could take around 1-2 hours, depending on how much shopping or eating you want to do.
Overall, there is plenty to do in Prestwick for a half day or six hours. It just depends on what you enjoy doing.