I cannot see how an external intervention to safeguard the Syrian state's stockpiles of chemical and other weapons can be separated from the wider context.

Perhaps an Arab League & UN intervention is an option for such a single purpose intervention. Finding willing participants will be a challenge and from memory the UN has found it hard to get competent military contingents, let alone move fast.

There are historical, regional examples when Western nations with small UN peacekeeping contingents moved quickly to intervene on agreed ceasefire lines when local and international agreement was present - that time is past (Canada & Scandinavian forces IIRC).

The most capable regional military power, Israel, has been very quiet on a post-Assad Syria and currently is reported as more concerned with the "far enemy" Iran.