Your Keurig will need 80 amps at 12 VDC according to your calculations. Since I believe your brew time to be minimized, I will use the time factor to be 10 mins. (maybe someone wants a second?). Theoretical amp hours used would be 13 AH at 12v but since Mr. Peukert is standing by with his constant in hand, that theoretical 13 AH will be more like 16. Also invited to the morning coffee table will be MS. Inverter Loss. She will account for another deviation of 6-10%. Thus, your morning coffee cabal will eliminate 17-18 AH, almost half of your usable amp hours from your Grp 24 battery.
I've read a few posts about the Keurig where owners could not operate them on a 1500 watt inverter. I think you would be better served by finding a different way to brew your morning Java.