By an oversight the federal government had not blockaded Minas Gerais and fuel trucks continued to head on its way. When they stumbled into the Tiradentes Detachment fuel, truck and driver were requisitioned into the column, keeping its tanks full in the field.

The next obstacle was the Paraíba river. If the 1st Infantry didn't want to defect, it already would have an impassable defensive line over it. It seems Kerensky was "successful" as even after his retreat the rebels spent hours in place and that was enough time for the 1st Infantry to reach the river. As it defected all of that was void. This is my own conclusion based on the timetable.

The vanguard crossed Três Rios at 10:30 and entrenched south of the river. An enemy jeep was spotted on recon, the enemy was not far.
The Armored Division now had battalions - 2nd Tank and 1st Armored Infantry - to the west, in the direction of the IInd Army's theater. The 1st Armored Infantry was actually on his side. The 2nd Tank may have deployed forces in the valley, based on a passing reference in the news, and its allegiance is a mystery. Muricy could only see the "fog of war" and accordingly prepared for the worst, sending the 2nd Police and an antitank company to shield his right flank.

Cunha Melo's forces had occupied the town of Areal for the whole morning, with explosives in the bridge. It was likewise confusing and intimidating for the locals. They entrenched between Areal and Três Rios, making contact with the rebels. Once again there was a frontline.
Cunha Melo had been Muricy's student; it was a professional, not personal conflict. And he was determined to fight. After checking his subordinates only Cpt Mendonça of his engineering company refused and got arrested.
Given how early Cunha Melo got to Areal it seems he could've won the race to the Paraíba, making his position much stronger. Perhaps he placed too much trust on the 1st Infantry? Sources don't touch on this but it came to my mind.

Another decision of his was entrenching between Areal and Três Rios; Muricy had identified the most defensible bottleneck as between Areal and Petrópolis. He was pleased to hear Cunha Melo chose the weaker position. Perhaps he wanted to conserve as much territory as possible?

Cunha Melo's objective was defensive, not just from lack of offensive orders, but also because the 1st Infantry's defection had changed the balance of power. Muricy considered he was now of equal or greater strength but still not ready for a regular open field battle. By noon he prepared an attack with the 11th Infantry and his group of howitzers. They'd get ahead of the column in a wider formation and charge enemy lines ASAP, even with a disorganized attack. The point was to strike fast to take advantage of the enemy not having much time to entrench. In the process they'd also get defections.
One source on the legalist perspective believed the 1st Group's 16 howitzers would've been brutal on a rebel attack, whether it'd succeed is not known. Cunha Melo didn't pick the best position but other sources still state it was excellent defensive terrain.