With the ceasefire largely holding, the Syrian Army and its allies can now focus on destroying ISIS

With the fragile ceasefire largely holding, the Syrian army and its allies have driven eastward into ISIS-held territory. And they've made significant gains in the last week:
On Friday morning in the southeastern countryside of the Homs Governorate, the Syrian Arab Army's 120th Brigade of the 2nd Division - in close coordination with the National Defense Forces (NDF), Liwaa Suqour Al-Sham (Desert Hawks Brigade), and Dara' Qalamoun (Qalamoun Shield) - continued their advance towards the strategic city of Quraytayn, striking the Islamic State of Iraq and Al-Sham's (ISIS) positions at the important hilltop of Tal Quraytayn.
ISIS is now facing attacks on at least 3 fronts:

In the southeast, the Syrian army is also closing in on the ancient city of Palmyra:
While the Russians were busy hitting ISIS positions in eastern Homs, the Syrian Arab Army's 67th Brigade of the 18th Tank Division was zeroing in on the ancient city of Palmyra, where they attempting to advance to from two different flanks.

The Syrian Arab Army's 67th Brigade - in close coordination with Liwaa Suqour Al-Sahra (Desert Hawks) - continued their advance inside Al-Dawa in the Palmyra countryside, seizing almost the entire village after a violent battle with ISIS. Meanwhile, to the northeast of Al-Dawa, the Desert Hawks and Panther Forces imposed full control over the small hilltop of Tal Halawa near the Ancient Palmyra Quarries.
This map shows just how close they are:
saa and isis map syria
The SAA controls the red areas; ISIS controls the grey
Of course, seizing the Caliphate's "capital" of Raqqa is still the end goal, and would have tremendous symbolic value for Assad and his allies:
[G]overnment forces have advanced along the M45-highway (Hama to Raqqah) and reached the western fringes of ar-Raqqah province while also completely repelling the ISIS offensive which had the government supply route to Aleppo cut last week. Meanwhile, Kurdish fighters of the People's Protection Units (YPG) and Syrian Democratic Forces (SDF) have taken firm control of the northern region of the ar-Raqqah governorate. Last year, Kurdish forces won a last-minute battle against ISIS at Kobane city. Moreover, the YPG seized upon vital momentum and remarkably captured the entire Turkish-Syrian border area which stretches from ar-Raqqah to Hasakah together with hundreds of ISIS-held villages.
A map of the advance on Raqqa:

saa isis map syria Raqqa
Russian airstrikes have been critical to the rapid advance. And speed is of the essence: As long as ISIS remains a serious threat in Syria, Turkey and Saudi Arabia can use it as an excuse to "intervene."