Introduction
I like heroes who are sometimes referred to as "good third heroes." Beravor and Gríma, among others, often fulfill this role. Théodred, who enjoyed great success in the early days of the game, isn't a powerful hero, but (perhaps even better) he's incredibly versatile at generating, redistributing, and smoothing resources, and brilliantly suited to enabling swarming, even in tri-sphere true solo decks like the current one.
Strategy
Otherwise there are no general rules in this deck. You systematically commit Theodred to quest by choosing who to assign the precious additional resource to. Sometimes it's Theodred himself, sometimes it's Glorfindel or Hirgon. The downside of this great flexibility is that you have to plan your budget and forecast your expenses for the current or next turn, depending on the needs of the moment, the quest step, or the scenario. Obviously a good swarm-army pace is the key, and Théodred is the key-holder...
One of the great strengths of this deck is that it's quite stable and able to adapt to very different scenarios without needing the sphere. Built-in healing is sometimes crucial. Ioreth can either help Glorfindel to save resources for payments other than healing kind (allies, Eldahir's action, Asfaloth or events), or simply magnify the Noldor's action in quests that heavily tax your hit points.
Adjustments
In scenarios that turtle a little, I would recommend substituting the side quests Gather Information, Prepare for Battle, and Keep Watch for the three Dwarven Sellsword.
The deck and its sideboard mainly uses RCO cards (except Asfaloth and two side-quests). But feel free to tailor it to your collection and playing style. Have fun !