You're looking at the wrong band for easy songs. I don't listen to them anywhere near as much as I used to, but I suppose In Waves is definitely one of their easiest. As I said though, this is the wrong band if you want something easy.
The intro to Strife isn't too difficult. It gets a little tougher after the intro though.
And Sadness Will Sear and Down From The Sky are both pretty simple but also both are 7 string songs so that might not work for you...
R.I.P. My Signature. Lost to us in the great Signature Massacre of 2014.

Quote by Master Foo
“A man who mistakes secrets for knowledge is like a man who, seeking light, hugs a candle so closely that he smothers it and burns his hand.”

I mean easy in the relative sense. I know Trivium isn't a walk in the park but I'm not a beginner so I think I can handle it.
Dying In Your Arms is pretty easy, even the solo.

Other easy songs where I haven't learned the solos would be:
A Gunshot To The Head Of Trepidation
Anthem (We Are The Fire)
Down From The Sky
Ember To Inferno
The Calamity
So how am I supposed to take anything you say seriously,
when you've swapped free will for faith, hope and pre-destiny?
I'd agree with BroDD that Dying in Your Arms is a relatively easy one for Trivium. From the Ascendancy album I'd suggest the main riff in Pull Harder and also the riffs in Rain are good to build up the tightness of your right hand and galloping speed.

From In Waves the title track is one their easier tracks and Watch the World Burn is a good one to learn as the solo isn't as complex as some of their others. Black and Built to Fall also.

From Vengeance Falls I'd suggest learning the first three tracks. The main riff in the title track is pretty cool.

Cheers, M
Built to Fall from In Waves is certainly one of their easiest songs, bar half of the solo
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