Do I have an accurate understanding of the following sentence?
むかしむかし、とても　おくびょう　だけど　心　やさしい　男が　山道を　歩いていると、どこ　から　ともなく、
こわーい　声がします。

"Long ago, a very timid yet kind-hearted man walks along a mountain trail, where a scarey voice is heard."

I feel like I'm understanding what the sentence is portraying in general, however, I doubt that I am accurately translating it. The tense, and どこから are my most uncertain points.

Question

Do I have an accurate understanding of the following sentence?
むかしむかし、とても　おくびょう　だけど　心　やさしい　男が　山道を　歩いていると、どこ　から　ともなく、
こわーい　声がします。

"Long ago, a very timid yet kind-hearted man walks along a mountain trail, where a scarey voice is heard."

I feel like I'm understanding what the sentence is portraying in general, however, I doubt that I am accurately translating it. The tense, and どこから  are my most uncertain points.

Answer

>I feel like I'm understanding what the sentence is portraying in general,

Yes, you are.

どこからともなく　＝　どこ＋から＋と＋も＋なく

＝（特定の）どこ（かの場所）から、と（いうこと）もなく、

literally ,"from wherever,  not".
or "from somewhere unknown"

Answer

In general, old stories are told in the past tense. ex.  the man was walking along.
But, sometimes the present tense is used to give an ON GOING effect. ex. 声がします
This style is OK in Japanese, but I am not sure in English.

どこからともなく　means He doesnt know where it comes from.
Please find an appropriate English.  
 A good translator is the person who can find an  appropriate expression.