Back out of all this now too much for us, Back in a time made simple by the loss (1-3)
Now entering the wayback machine. With an echo of the famous William Wordsworth poem, Frost shows us how we can escape all the complications of now and travel back to a simpler, idealized past. What makes that past simpler? Well, simply the fact that memory has blurred out a lot of the detail. In other words, it seems simpler because we can't remember it all perfectly.
There is a house that is no more a house Upon a farm that is no more a farm And in a town that is no more a town. (5-7)
Remembering the past can get a bit tough at times, especially when you realize just how much things have changed. Houses are no longer houses. They're holes in the ground. Which is, you know, kind of depressing.
Where were they all not twenty years ago? (26)
With a question like this, Frost sounds like every old coot indulging in nostalgia. Here he's talking about the trees that didn't exist and are now acting all high and mighty, excited and flighty, like the upstart whippersnappers that they are. Right, where were they? And what does that say about the way things are now?
Make yourself up a cheering song of how Someone's road home from work this once was, (29-30)
If you're getting bummed out by this trip back in time, seeing how time has trampled all the old things, here our speaker suggests you sing a happy song to cheer yourself up. It might help to imagine the productive life that once thrived where you're walking—and to imagine that it could still exist.
Some shattered dishes underneath a pine, […] Weep for what little things could make them glad. (42-44)
There's nothing quite so depressing as an abandoned playhouse scattered with broken toys. It practically screams out, "lost innocence," doesn't it? Here, our speaker is so bummed out he practically demands that we cry along with him. Why? Because those kids were so simple and innocent that they could be made happy with even the smallest of things. All they really needed was imagination.
I have kept hidden in the instep arch Of an old cedar at the waterside A broken drinking goblet like the Grail (55-57)
Do you have memories you like to return to again and again? Maybe they're your "happy place." It sounds like this place is one of those memories for the speaker. He's been there many times, so much, in fact, that he's stashed the broken goblet he stole from the kids' playhouse for times when he returns. Along with references to cellars (where you store things for later), this goblet recalls another time (legend even) and it becomes a vessel for return.