SoggiornaPonti Romani is the easiest route in this group: number 2 on the Finale Outdoor Region map, cross-country, easy to intermediate. Downhill it links Le Manie with Finale Ligure; uphill it is a good way into the 24h area and the trails around it.
It never turns into singletrack: it stays wide, with pleasant gradients and a surface that keeps its grip even when wet.
Along the way you ride over or past three bridges, which are actually medieval although everyone calls them Roman, and you can stop at the panels telling the story of the Via Julia Augusta. Before you set off, check on the Finale Outdoor Region website that it is open: trails close for maintenance, races or bad weather.