I believe Walk Away hit it right with that interpretation. While I'm not going to deconstruct the song (or at least parts of it, the way Walk Away did), I'd like to add a few interpretive points myself.

I believe this song conveys a sort of mood or feeling that strikes a lot of people when the reach a certain age in their lives; a mood or feeling caused when someone enters into an extended state of reflection concerning the life one has lived. This state of reflection may come and go, and last anywhere from mere seconds, to minutes, to days and weeks. It's the sort of reflective state that often precedes- for example- what some like to refer to as a "midlife crisis," however, I do not believe that this song is about a midlife crisis, as much as it is about the wave of disappointment that often sweeps people during this reflective state; disappointment concerning the life one has lived, and how (this person experiencing this feeling) it hasn't culminated to what one deems an 'accomplished' life; a life lacking merit.

At this point, people (in their realized state of depression, resulted from that state of reflection) will begin to think that their lives have been lived wrong, or maybe even if it's a state of nostalgia, they wish that they could go back and change things they regret having done (or maybe that they hadn't done earlier, in terms of both time and place). Here, they feel trapped by time, including by their own age, and that there is virtually nothing that will change that.

Graffin, in Avalon, who writes from an obvious understanding of this feeling of a wasted, or unsatisfactory life, instructs such people to -basically- "suck it up," or "bite the bullet" and construct a life worth living for oneself... that only you are responsible for your own happiness, and that dwelling on the past is only going to delay that act of creating a life worth living for yourself; finding your Avalon. He's not criticizing the initial feeling or mood itself, only saying that one cannot stay disappointed and depressed forever, for it is something we, as humans, all go through.

I see this as a counterstatement to the often proclaimed "Life is futile" even when life is rough and seems to be futile. There is purpose in the end, and that purpose will be realized in the future.

This song is about how people which have an obscure or criminal past tend to be terrorized by these memories

This song advises not to be too bummed out but rather move along and strive for utopia.

This song is about time and our lives, and how we have to find our own personal salvation in a world where there are so many ideas of what is right or wrong, especially religiously.

Avalon is a major part of Arthurian legend, where Excalibur was forged and where Arthur eventually goes to "heal" from his wounds, although many see it as a place he went to die.

From this context, Avalon is our beginning (as drawing the sword from the stone was for Arthur) and our end (like wise).

The first verse points out the isle of Avalon with the wind blowing in from the sea, which is our world. We're brought into the world without a real direction, and time still continues to pass. Eventually, we'll all reach the same end and simply living a life tending to others ideas or desires without embracing our own will make this existence a "mundane" one.

The road to paradise refers to the way to reach Avalon, or what is beyond our own world. There is no easy way to get there, as even Arthur was wounded before he sailed for the island. We have to accept the reality of our physical world and of time which we have no control over. Humans need to contemplate what our actions really mean in the grand scheme of things.

The final verse simply describes the end of our days, and how what is here on the physical earth is all temporary and will decay in the same time we ourselves decay. All of our moments are subject to the constraints of time, past and present, and eventually future.

The chorus is of course a call for a person not to think about their past and what took place in it, but to push forward in finding a destination or goal to move towards.

That's just my 2 cents, if anyone else wants to chime in to try and clarify this a little more I'd love to hear it. This song is something I'm trying to wrap my head around.