Several trails, but mostly paved roads in the area. From Nanshijiao MRT station, walk towards Myanmar Street with plenty of restaurants. Then another 15-20 minute walk and you are at the foot of the hill. Several different ways lead up the hill. Some more steep paved little roads but also some pure stairs which is bad for your knees but could to avoid all traffic.
Record for many temples!
Nope
Myanmar Street in New Taipei (make sure you taste some typical Myanmar food on the way back - like Hibiscus rice)
no guide needed
From Nanshijiao MRT station, you could walk through this area of New Taipei and after a 25-30 minute walk along sidewalks (and sometimes climbing over scooters...) you will reach the foothills of Hongludi. Then, it is uphill for about 45 minutes through paved roads or alternatively via stairs or you can take a small bus directly to the Hongludi parking area. There you can explore several temples dedicated to wealth, money and also happiness and long life.
Traffic and people. Especially on weekends in the afternoon, there might be a lot of road traffic. But overall great place for a simple hike. The main road or path to the temples is not long, but steep and with many steps. Maybe about a 1000.