Magome/Tsumago to Narai

Hello,

We'll be visiting Japan soon and will be in the Kiso valley to walk along the Nakasendo highway. I know Magome to Tsumago is very popular and is only about 8-9 km. Being from Montana, we do quite a bit of hiking and 8-9 km is probably not going to take up much of our day. It didn't seem like there was much else to do in either post town, so I'm wondering if we can hike the trail further. I've heard conflicting information regarding this.. But is it possible to hike to Narai from Magome in a day? If it is, I'm thinking we'll start early in Magome, make our way up the trail, and book accommodation in Narai.