Hi there -
I think you'll love the CR North Wing. Yes you definitely can walk from North Wing to MK in about five minutes. Taking the monorail there will actually take longer, since you have to stop at all the other stops before reaching the MK (about 15-20 minutes). It is fun though. On the way home from MK, we usually take the monorail - line is seldom crowded for resort monorail and the CR is the first stop, and we are TIRED.
I recommend you ask for the wing of the building closest to the main tower, especially as your mom will be with you, as it can be a long walk to the end of the other wings. The main building is only a few steps from the side door, you go right in on the Ground Floor (Food and Fun Center). They have a small food court - good fries - and a refillable mug program, and a large arcade. Up on the fourth floor are all the shops as well as the steakhouse and Chef Mickey's.
Definitely take a ride on the elevator up to the fifteen floor for the observation decks, one is on the right side of the California Grill, and the other on the left is through the restaurant itself. Great for fireworks watching, and to see the Castle's Kiss Goodnight! Great fun even just to see Space Mountain and the Castle in all their glory.
The Electric Water Pageant passes by the Contemporary lagoon every night at about 9:45 - they pipe music in to go with it. My five year old loved this!
Hope you have a great stay!