Around the old castle ruins in Obi is an area of former samurai residences. Closest to the castle were the highest ranking samurai, moving down the ranks further away from the castle until you reach the old merchant district.
Being somewhat off the beaten track the area has retained many of the buildings and the basic layout of these former times and is registered as a Historic Preservation District of groups of Traditional Buildings. There are more than 100 of these districts scattered across Japan, and while some are in major tourist areas, many are not.
I've come across quite a few on my walks in the backcountry, and in my experience some of them are quite delightful, being non touristy and ungentrified. Links to many of them Ive visited can be found at this index over at Japanvisitor.
On this trip I was in a hurry to carry on with my pilgrimage, but recently I revisited the area and spent time exploring in the houses open to the public and can recommend it to visitors to Miyazaki