The alert has been on for a while at Mayon, a few weeks now. There'd be ample warning if going there was imminent danger, plus any Route Markers from TARA/TARAu (Cagsawa Ruins, Barangay Budiao, Daraga and Misibis Bay) are a safe enough distance away? Especially if they're going in the next day or two.
And question, have all the Switchbacks always been at the same exact location?
I can't recall. The cheese and the head shaving Switchbacks were at different locations, so...Because while it may be a little crazy in the province of Cavite (sorta), they could easily stage a field plowing task pretty much anywhere else in the country.
I think they'll be staying in Luzon though. So I think the best TARPh-used northern locations that are possible would be Baguio City and Mountain Province. They'll be able to do cultural tasks and the rural area is stunning (the rice terraces) and definitely provide a chance for an Ox/field plowing tasks.
Especially since this route hasn't had any rural locations yet? I'd think they'd use the Philippine countryside more than Metro Manila locations outside of a Route Marker or two, like Baclaran Church, to get them out of the city.