It’s best to plan a trip for the weeks between Thanksgiving and Christmas. I understand that the first week of December is VERY quiet.
I would recommend the Pop Century Resort. If you can spend a little more money, then Port Orleans French Quarter is an absolutely beautiful little resort - I know you and your mother would love it. With staying on site you get many perks - all your transportation, plus you can use Magical Express to and from the airport - that alone saves money and it is so easy and convenient. You are also able to participate in the Dining Plans which Disney offers. There is a sticky in “Restaurants” which explains the various plans and the prices. As a guest, Extra Magic Hours are offered to you - meaning you have early entry into the various parks - morning or evening - on certain days. Of course there is the added bonus of being able to enjoy the Disney magic 24 hours a day. It doesn’t stop when you leave the parks. All the resorts are fun and all will be dressed up for Christmas.
Mickey’s Very Merry Christmas Party takes place in the Magic Kingdom throughout the Christmas Season. it is a ticketed event, but there are TONS of events throughout the parks that are free - the parades, the decorations in the parks and resorts,(the Gingerbread House in the lobby of the Grand Floridian is a must see), the amazing Osborne Lights at the Hollywood Studios. The Candlelight Procession at Epcot - all free and all wonderful.