Can Nico Robin really reveal the void century? Nico Robin's goal is to find out what happened in void century that written in poneglyph, and she must read all the poneglyph to know the history.
Poneglyph is said scattered around the world, and each poneglyph is connected to another poneglyph.

But can she really read all the poneglyph and reveal the void century?

Because if I'm not mistaken about the Log Pose, it will point to the nearest island. How about there's some island missed by Mugiwara Crew and possibly have a poneglyph, that's mean Nico Robin can't read the poneglyph and she also can't reveal about the void century.
Yes, she can.
What you said about her requiring to visit all poneglyphs to decipher the Rio Poneglyph is true and has been stated in the Wikia also:

Only when the stones are read as one will they fill in the Void Century of the world.

However, it also says:

There are two types of poneglyphs: those that carry information about how to reach the other poneglyphs and those that carry the records of the &quot;True History&quot;.

Hence, even if she were to miss an island, she would be guided there by another poneglyph. Finding the island is not much of a problem either because one can use an Eternal Pose:

Like a Log Pose, it records the special magnetic waves of a certain island within the Grand Line, allowing the user to know which way to go to arrive at their destination. Unlike a Log Pose, which resets its recordings on new islands, an Eternal Pose always points to the same island, no matter how long it stays elsewhere.
They appear to be available for purchase, though come at a high cost.