Hi Tigger2on. I'm sorry to hear that you're thinking of cancelling your plans. When I just checked the Southwest Air website for a non-stop flight leaving December 26th (~7:30 a.m.) from Buffalo and a second non-stop flight returning January 3rd to Buffalo (~ 10:30 a.m.) I got a price of $1,068 USD for 3 people. (I think those were your dates from responding to another post on the Theme Park Strategies Board). That's even what Southwest calls a refundable fare (meaning it's refundable and changeable but I'm sure there's some fine print).
Okay - hotels. How about staying on-site at a value resort for the first several days? Pop Century (and I think ASMu and ASSp) is charging $127.68 USD per night up until the 31st, but on January 1st the prices drop to the value season rates, and maybe you could spend the last few days of your vacation in a deluxe resort or get a good rate in the value resort. Disney will arrange to have your bags transferred while you have fun in the parks.
Okay, now that you're staying on-site, you won't even need that rental car. Another $310 USD saved!
Fingers crossed for you. The Thanksgiving trip sound like it would be fun, too!!