Like Mike above, I thoroughly enjoy McCullough’s Masters of Rome series. However, it should also be noted that Caesar’s Women ends in 59 BC and the next novel in the series, Caesar, picks up the storyline in 54 BC, so she only covers the later portion of the Gallic War.
For more detail and focus, I highly recommend Conquest of Gaul, the second volume in the Marching with Caesar series by RW Peake. The novel is told from the perspective of Titus Porcinianus Pullus, loosely based on Titus Pullo, a historical centurion in Caesar’s 11th legion. He was also the inspiration for the character of Titus Pullo in the excellent TV miniseries Rome.
IMHO all three of the above are filled with highly engaging characters and terrific period flavour!
"Ventosa viri restabit." ~ Harry Field