This is my take on an Arrows from the Trees deck. With three spheres, the resources can be a bit tricky, which is why both Errand-rider and Narvi's Belt are included. The card draw is quite good - particularly with Heed the Dream (don't be afraid to use the kicker if you really need a key card), so you should be able to get everything setup to play Arrows from the Trees at least once. Steward of Gondor should be attached to Thalin, to help pay for expensive tactics allies as well as the kicker on Arrows from the Trees. I did not include any ability to recycle events because you should not need to use Arrows from the Trees too many times before you have control of the staging area.
It goes without saying that a deck like this fairs better when paired with other less-niche decks. An all Hobbit deck featuring Lore Pippin is a particularly good match, as is a Dunedain deck that can take some of the early enemies while you get yourself setup for the big combo. A spirit deck with questing and some cancelation is a good idea for quests with direct damage and/or nasty treacheries. Sneak Attack has many targets with this strategy, so don't feel like you have to wait for Gandalf. If you have Sword-thain and Anborn in hand, that is a great way to turn him into a hero. He can then attach Wingfoot and take advantage of Seastan's hilarious ever-ready Anborn combo (hint: name Enemy). Otherwise, the eagle loves to bounce around during the quest phase and generally create havoc.
Even without Wingfoot, Anborn fits in perfectly with your strategy as he can increase the engagement cost of an enemy that would otherwise engage. Getting an additional damage on top of the one from Thalin is a nice bonus. Enemies stuck in the staging area while you build your combo can be sniped with Haldir (hopefully equipped with a bow). There are a lot of "soft" combos in this deck, so it should not fall flat if you cannot get everything in hand. Ideally, you will have a Beorning Beekeeper in play (it's nice having an excuse to play my Beorning brethren) or a sneaky Descendant of Thorondor in hand. Along with Thalin, Sword-thain Anborn and a copy of Arrows from the Trees, the enemies are in for a bad time. With Steward on Thalin you can afford the kicker on Arrows and basically wipe out everything in the staging area. A combo with this many moving parts is not going to hit every time, but it should be a heck of a lot of fun when it works.