So you might be familiar with the fact that adjectives in Japanese come in a few flavors: Na-adjectives, i-adjectives
You can now add "no-adjectives" to your list. It is not official as far as I know, but thinking it over I think it will be easy and clear to you:
Some examples before I get to your sentence in question:
"adj before noun"
爽やかな 風 が 感じました (sawayaka + な)
大きい帽子をかぶっていた (ookii + (nothing), but ends in い)
たくさんの人が来ました (takusan + の)
When you want to modify a verb with "adjectives" they change in this way:
"adj before verb"
さわやかなように 触った (~なように sawatta)
うまく出来た (umai -> umaku)
まったくない (no special change)
So that's how you can connect adjectives/descriptive words on a basic level. You might call them adverbs once you connect, but the word choice in English doesn't apply 100%/ひゃくぱ.
As for boku (me),
In [the] surroundings, nobody [was].
You're right that ひとりぼっち means alone/solitude/loneliness. The same could have been said by saying ひとりで but that just means "by oneself/myself" instead of "totally alone"
So your sentence, put together, means something like
I was completely alone; nobody around.
Japanese does not start with the assertion of an "I" or a "subject" that is modified by verbs and adjectives like in English.
Often people will translate things like this by saying "Okay, there is an Identity, and then the rest of the sentence modifies the identity"
Actually, it is quite the opposite in Japanese, we simply state the situation as clearly as possible. Whether or not there is a subject involved is usually irrelevant or delegated to context. So for example,
If we remove 僕は we have
Completely lone, surroundings containing [absolutely] no one.
When translating and interpreting, I encourage you to read every statement as a situation, instead of as a subject verbing. You will see this sort of aspect most readily in statements for hunger and thirst:
お腹 が すいた
Stomach が Empty/Hungry
のど が 乾いた
throat が dried/thirsting.
If there is a relevant "part" it will be stated, but otherwise, we are simply painting a scene with a brush that cuts through identity.
Hope that answered your question and gave you some food for thought.
Edit: "When can an adverb use の to modify a noun?"
All the time provided it has no -i or -na counterpart (which would be used instead)