There are several, clearly marked trails. Mostly these have stairs and cobblestones.
Highest mountain in Yangmingshan area. And it is the highest volcano in Taiwan.
no
Menghuan Hu Parking and nearby LengshuiKeng have toilets and small stores so you can fill up on water. Do not expect a full service restaurant and better to bring some food from the city.
no guide needed
Qixing is the main peak in the Yangmingshan area north of Taipei. In this volcanic area, you often have more wind and a cooler climate as down in Taipei. The difference is sometimes 10 degrees. From a bus stop a typical hike is a round trip of about 3 hours that includes the top of Qixing. It is very step with lots of steps, but overall a moderately easy hike. Just make sure you get prepared for all weather conditions.
Can get cold. Often 10-12 degrees colder than Taipei.