I ended up being able to furnish a handful of FotR decks. I didn't have enough sites for each deck, so instead playing a site means just searching through the site deck for the next site on the path. You can't replace a site you put down (e.g., using
Pathfinder), but you can pick your site based on the scenario. TTT is okay, though if you can find some FotR cards I would include them. Towers Block, even in a controlled environment, is more boring to me than Fellowship Block most of the time; combine the two and the possibilities grow exponentially. I used only sites from 1 block, but mixing and matching is fun too.
I explained the rules more-or-less as I went. I had a sample game set up to show basic mechanics (how the board should look, wounding, skirmishing, etc) to try and garner interest.It helps most people if you tell them what's similar about Magic (a game I am not very familiar with, but it's easy). Events = Instants; Conditions = Permanents; that sort of thing. I think that having a scenario set up in advance just makes things look more appealing than cards strewn out or, worse, stacked in decks. Gives people something to look at in context. I talked about the twilight pool and card types and how the deck is made up of two forces with the sample game, but just about everything else I explained in-game. I let people pick what deck they prefer (I had 6 to choose from, 7 including the one I used) and explained the basic strategies (choke, swarm, archery, beatdown, etc.) so they could pick something that might suit their play style. Playing with open hands (i.e., both players can see what the opponent has in their hand) might be a good idea too, as long as
you never use that information against your opponent. You already know how to play and what moves to make; just let the other person enjoy the game.
All the decks had starting companions picked out, and I purposefully played a sub-par deck to help my opponents feel more in control. The first time one of us played a Fierce minion, I would explain "Fierce" right after that minion was played. Same with Damage +1 and Archer. I used a counter app to monitor the twilight pool and small coins for burdens/wounds, though you can probably do better than that. A 20-sided dice would be easy to keep track of twilight, for example. One thing I wish I had was a chart of the phase order the way it's shown in the starter rulebooks; I know I had to reference it constantly when I first started.
I don't know what the setup is like, but since I assume it'll have lots of people make sure not to set up in a corner. I made a sign out of a regular piece of paper saying "LotR TCG - give it a try!" or something, with a note saying "~45 min" to let people know it's not a quick game. A training game will probably take twice as long, though. You might want to print something out, the front page of the starter rulebook is a good idea (unless you've already got some). Most importantly, don't worry if very few or even no people come by. Try to figure out what would've been helpful for you to do and just do it next time. I definitely did better on my 3rd try than my 1st and 2nd because I saw what wasn't working and thought up ways to improve. Good luck, and let us know how it goes!