It doesn't seem worthwhile going E/W on Frodon. If he doesn't turn up you are doubling your loss. Far better to split the stake as win/win Betfair and Gold Cup. Even if Frodon does run in the Gold Cup it seems unlikely to me that, if he doesn't win it, he would be likely to place. The distance of the Gold Cup has always been one of the biggest negatives and if he is going to be beaten I suspect it will be pretty comprehensively on the day.
Frodon was actually the highlight of my Cheltenham last season, when I took an early view that he would not run in the Gold Cup and backed him for the Ryanair at 16/1. 9/2 on the day, he was game in winning it and it seems a bit odd that he is as big as 14/1 to win it again. I don't think the Betfair is the right race for Frodon. Bristol De Mai pretty much owns the race and will likely set out to run his opponents into the ground from the start. That will make life tough for Frodon and Altior and I doubt the Betfair is the right race for the 2 mile champ either, I feel it would be suicidal running Altior if the ground is at all testing.
For me the Betfair rests between Bristol De Mai and Lostintranslation. Lostintranslation needs more and at 2/1 he isn't making nuch appeal when the "Been threre, done it, bought the T-Shirt" horse is only quarter of a point shorter in the betting. The Tizzard horse is very unexposed at the 3 miles plus trip though. He seemed ready for a step up in distance when losing out to Defi Du Seuil twice and duly obliged when upstetting Topofthegame in the Mildmay. Lostintranslation seemed near his best in his return to action this season and given that it was back in distance to 20F and probably short of what is likely to be his best distance this season. Lostintranslation looks a raw sort who still has some filling out to do and he has scope but he will be facing a horse in Bristol De Mai who seems to be a different animal at Haydock than anywhere else and he can sustain a strong pace that wears opponents down, most noticeably when crushing Cue Card in a devastating show of how to grind other horses into submission.
I would be loathe to oppose Bristol De Mai in the Betfair on soft ground and foresee problems for some of the entries.
If Frodon were my horse I would skip the Betfair unless it cuts up quite badly and the ground is decent. 14/1 for the Ryanair appeals to me as the best bet ante-post for the prolific winner.