This is a poem that many people, even scholars, would have to re-read a couple of times. That doesn't mean it's especially difficult – that's just how some poetry works. Frost tries to recreate the sense of tired, dream-like reflection just before sleep, and people don't often think in a linear fashion during that time. Also, there are some details – particularly the detail about ice frozen at the top of a water trough – that date the poem to an earlier historical period. But as long as you're willing to tolerate some ambiguity in the themes and language, this poem shouldn't be anywhere near as hard as having to pick "ten thousand thousand" apples while perched on a ladder!