Morton House was the dower house of the Trotters of Mortonhall. The original east part dates back to 1709 (carved on the dormer) and it is believed to have been built by Thomas Rigg on the site of an earlier residence. A new entrance, late Georgian in appearance, was added at the beginning of the 19th century.
Not far from the house itself is the belvedere, standing quite impressively in a small field with great views to the Pentland Hills. It probably dates back to the early 18th century.
From (near) the cache, you can see the back of the house, as well as the belvedere. Also good views over farmland to the east. I would also recommend walking round to the front of the house to see the impressive gatehouse pavilions. To get there from the cache, walk past the belvedere and turn right at the children's nursery.
Parking is available on Frogston Road. I've marked the cache as wheelchair friendly as the route to the cache is essentially along a private road. However help may be needed to reach the cache itself.