This riding arena with outdoor facilities and a solar roof lets you train and keep your horses fit exactly how you want.

Price: $15,500
Maintenance: $50/day
Earnings: $60/hour

Jumps and markers, which you can configure alphabetically, are available for individual, purchase in the Build menu under Decorations / Other.
Design your own course. And if you no longer like it, you can simply sell them again for free.