My daughter & I visited 4 chateaux in the Loire Valley recently & we spent a couple of hours visiting each one of them.
Our time was limited because we didn't have a car & had to return to the bus stop after 2 hours, to go to the next chateau, or to return to Amboise.
Our favorite was Chateau Chenonceau, mainly because of it's beautiful setting & it's architecture.
There's a delightful tree lined promenade leading to the castle. Part of the castle is built on what was once a bridge across the river & it's surrounded by an immense forest. The history of this castle is very interesting too. I enjoyed the lovely fresh flower arrangements in the various rooms, & the 2 very different gardens. We had wanted to walk in the "maze" garden, but it was closed to the public when we were there.
Chateau de Chambord was interesting, the castle is huge, but only part of it is open to the public. We enjoyed going up to the roof to admire the scenery of its surroundings.
The double spiral staircase was unique. I really didn't like the smell of the (multitude) wood burning fireplaces.
We had a nice picnic on the grounds before visiting the herb garden & the donkeys!
Chateau de Chevenry was very unique because of the hound dogs which are still used for hunting, but the castle's architecture is not that of a castle, in my opinion, as it looks more like a huge mansion, not a castle.
Chateau de Blois, was our least favorite. It's right in the middle of the city, without the beautiful surrounding like the other chateaux. We only toured the oldest wing as recommended by RS.
Unfortunately, we did not have time to tour the interior of Chateau d'Amboise, but it's exterior is beautiful.
We loved our stay in Amboise, it was so peaceful & quiet...
It sure sounds like you're planning an amazing trip, enjoy!