All of the trails are away from any major roads, some go near a couple of small streets within the park (at least on the map) but since people drive slowly if at all i doubt you would be able to hear anything. Ive been on most of the trails and havent heard anything.
Definitely, sometimes u might hear a plane pass by but the roads are pretty far off you won't hear any of the cars. It's very peaceful
To access hiking trails you have to access the main park entrance.
Yes
Yes they are very quite
I have only been there once and on 1 trail there are many trails as I'm sure you know, the one I went on yes it was isolated away from roads and from what I could see from the others I would say those are the same also
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