Hmm, just how willing are you to "slum it?"
If you are willing to stay at Wyndham Bonnet Creek, you could get a really nice room and still be on property. Heck, you'd be next door to CBR. They have a complimentary shuttle to the parks and beautiful amenities.
High end:
7day PH x5 = $2135
WBC Executive Family 2-Queen +Bunks for 9/30-10/9 = $1992 after taxes and fees
Leaves you $1452 to spend on food and match your current deal ($5579)
Low end:
7day base tickets x5 = $1790
WBC Deluxe Double Queen for 9/30-10/9 = $1612 after taxes and fees
Leaves you $2177 to spend on food and match your current deal (or spend less to help pay for that stupid a/c and car

)
I know you want to stay at a Disney resort and I think staying up on Thursday is a good idea, but if the room you need doesn't come available this is a really nice backup plan IMO.