Since Erestor and Caldara are both cards that people build decks around, I wondered if I could combine them in a single deck. This is my attempt.
The thought here is that Erestor can help you cycle allies into your discard pile more quickly than usual, which can then put into play with Caldara; and that his fast cycling might also help get Prince Imrahil into play and maybe even Sword-thain on someone to boost the number of those allies Caldara could actually put into play.
Cards to look for in your opening hand are Protector of Lórien, since it allows you to turn the inevitably-dumped cards that aren’t given to Arwen’s ability into additional willpower or attack bonuses, and Silver Harp, since it allows you to carry over cards you can't yet afford for another round. If you do get Silver Harp, then Prince Imrahil's good to see, since you want him out so that when you trigger Caldera you get two allies and not just one; but if you don't see Silver Harp, then you should mulligan to avoid Imrahil to increase your chance of getting him later. The third resource you should save so you can buy a four-spirit resource in round two. (The one exception is if you get Treebeard, in which case you may want him out on the table right away — depends on the starting situation.)
After this, you're trying to buy a good, 4-resource ally ever other turn. It's good to buy up the cheap stuff while you can — don’t forget you can get Erebor Guard for 2 through extra discard— but do save a spirit a resource in off rounds if you can manage it. If you can, you want to get a Sword-thain onto a spirit hero before you trigger Caldara, so that you can get an extra ally out (three, if you’ve found Imrahil).
Probably you'll delay triggering Caldara until you've either found Imrahil or gotten a Sword-Thain on an ally, but of course sometimes you may need to move more quickly. Another thing you're trying to do is to get Glorfindel & Jubayr in the discard pile before you have to/want to trigger Caldara. But, again, it depends on the situation.
Try as much as possible to use the otherwise-discarded Erestor cards for something — 1 per round goes to Arwen, of course, but they can also be used to fuel Steed of Imladris and Protector of Lórien.
I'd love to hear people's thoughts...