Nakasendo Walk - well-marked?

My friends and I are planning to do the Nakasendo Walk this April. We just copied an itinerary from a travel agency. Our itinerary:

Day 1: Walk Magome - Tsumago. Overnight in Tsumago.
Day 2: Walk Tsumago - Nojiri. Then train to Kiso-Fukushima. Overnight in Kiso-Fukushima.
Day 3: Walk from Kiso-Fukushima up to the Kaida Plateau on the Hida Trail. Overnight in Kaida Plateau.
Day 4: Train from Kaida Plateau back to Kiso-Fukushima. Walk from Kiso-Fukushima to Narai (passing through Torii Pass).

My questions:

1. Is the trail we plan to take (Magome-Tsumago-Nojiri. Kiso-Fukushima-Kaida Plateau. Kiso-Fuskushima - Narai) well-marked? We won't be taking a guide, so we'll need to navigate on our own.
2. I can't find any information about the trail from Kiso-Fukushima to Kaida Plateau. In fact, I was told that I have to take a bus there, and not walk. If this is true, where is this Hida Trail that is mentioned? Does anybody know of this trail?
3. Any comments/suggestions on our itinerary?

Many thanks.

Katsby
My questions:

1. Since we're doing this

http://www.japan-guide.com/forum/quereadisplay.html?0+100397

The above is a link to a question about the Kiso Valley trail from a few days back and an answer has been posted - maybe it will help you.

Hi katsby
The following is based on my memory of walking this route in 2007.
The route from Magome to Nagiso is well marked with signs and easy to follow. After that the signs are far less frequent. You will definitely need a map. Having said that, up to around Kiso-Fukushima, you are basically following the Kiso River up the valley, so the chances of getting lost are slim. You will also be walking on the main road for long stretches. This is also the case further up the valley. At some places the traffic is very busy and includes large trucks. To be honest, it was rather unpleasant some of the time.
After Kiso-Fukushima the route gets a bit difficult. In fact I remember we got lost at one point between Mienokoshi and Yabuhara.
The route over the pass from Yabuhara to Narai is a popular hiking track and well signposted from memory. But again, take a map.
As for the Kaida Plateau and Hida Trail, these are not on the Nakasendo and I have no knowledge of them.
Incidentally, our itinerary over this section of the Nakasendo was:
Magome - Nojiri (20.6km)
Nojiri - Kiso-Fukushima (28.1km)
Kiso-Fukushima - Narai (21.7km)

Forgot to add, you can read my account of the Nakasendo walk here:
http://thewalkingfool.blogspot.jp/search/label/The%20Nakasendo%20diary

I'm interested in walking the tsumago magome part too.. is it save for solo female traveler? Is there many people walking the track around late may?

Thanks..