If you ride more than it is safely able to hold then you will probably end up getting a helicopter ride out of there because there is some serious Trails there so if you have too many Riders then find another four wheeler somewhere. It's better to have a good time without any event.
The law states that you can only have the total number of riders that the ATV manufacturer list on the ATV. I have however saw many 4 wheelers with 2 people on them
You definitely can if your atv is made for it. Even if it's not I have seen lots of people do that though. I don't think that anyone get you in trouble for it.
Not sure if legal but have many times and was never questioned.
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