Here's a deck that I built with one core set to overcome the three scenarios of the ToS expansion. Note that I tried to stay within the theme, that's why you won't find Steward of Gondor, Faramir or Protector of Lorien in this deck. In other words - if you don't care about theme, you can make this deck even stronger. The deck has a total of 52 cards which is acceptable because of Bilbo's card drawing ability.

Heroes:

1x Sam Gamgee

1x Pippin

1x Bilbo Baggins

1x Aragorn

Ally: (21)

3x Gandalf

3x Treebeard

2x Bill the Pony

3x Quickbeam

3x Wandering Ent

3x Mirkwood Pioneer

1x Henamarth Riversong

3x Booming Ent

Attachment: (20)

3x Sword that was Broken

3x Dunedain Warning

2x Hobbit Cloak

2x Self Preservation

3x A Burning Brand

2x Wingfoot

3x Fast Hitch

2x Ent Draught

Event: (11)

2x Sneak Attack

2x Secret Paths

2x Rumour from the Earth

2x Entmoot[

3x The Three Hunters

Strategy:

This deck pretty much plays itself. You possibly want to have Treebeard ASAP to get the additional resources, and of course Sword that was Broken is one of the most valuable cards, so it's nice to have it in your starting hand.

Hobbits and ents offer a great lot of synergies. Your starting threat is low and Pippin's ability makes things even better. While laying low you can build up an army of Ents to pimp up your stats, especially your HP.

If you're getting to much threat during the start of the game while keeping enemies in the staging areas, you have the Pioneer and Secret Paths to make questing easier. Mirkwood Pioneer is one card that I overlooked for quite a while, but now I think he's one of the strongest 2 HP allies out there, almost a must include for lore decks.

The fighting is mostly easy - either you block attacks with your ents, or you build up Bilbo into a defense machine that can defend multiple times, cancelling all the nasty shadow effects (beware though that Burning Brand does not cancel the magic effects). Self Preservation helps Bilbo (or Aragorn) to keep his health in case his DEF is not enough to block an attack completely. For attacking you have your Booming Ents or whatever Ent is currently available.

Most cards are costing 2 resources or less, so resource managment is not a big problem. I never missed Steward of Gondor when playing this deck.

Wingfoot synergizes nicely with Henamartn or Rumour from the Earth, keeping Aragorn ready most of the time (not that you really need that, these cards could be replaced with some other stuff if needed).