I reckon they'll go to Ireland at Christmas and duck the King George.
There are a number of possibilities that can explain his run yesterday. Not being as fit as Cue Card is the most likely. But it can't be ignored just how good Cue Card was, and even if he was in top form he may not have been good enough.
If you take the last two Gold Cup's literally and assume Cue Card had stood up and finished in a dead heat, on the numbers (back me up EC!), Cue Card in my opinion would have been around 5 lengths ahead of Coneygree. There's some assumption there with where CC would have finished. I'd think he may have won, where others would argue he would have been beaten. Either way I'd contest he'd have been wishing 5 lengths of the winner. In a match in March it would be Cue Card for me and it wouldn't need a moments more thought.
Other explanations for yesterday could be that Coneygree is not quite the same horse, he doesn't act in deep ground, he needs De Boinville, etc. It should also be considered that he could bounce next time. Alternatively he could be absolutely spot on. Given all those variables, for a horse that could go either forwards or backwards at Christmas, and in my opinion is more likely to go to Ireland, 6/1 for the King George is no betting proposition at all, and I'd rather take the price about Cue Card winning the bonus which I'd say is considerably more likely than Coneygree winning at Kempton.