Woodcutting can be trained by cutting down trees, chopping ivy, and various other methods.
level 99 woodcutting.
cut willows until level 70 woodcutting then cut yews until 99.
Get 99 woodcutting and buy one
This entirely depends on what level you are starting at and what you are using to train the skill.
You will need around 67,566 yew logs cut to get from level 75 Woodcutting to 99. a deuce load of yews im on 70wc so I need a deuce load
There is no woodcutting guild (I wish there was tho)
You have to use a hatchet for woodcutting.
Woodcutting
you should stop woodcutting
Achieve 99 in the woodcutting skill and talk to the woodcutting tutor. to get to the woodcutting tutor from lumbridge court you walk out of lumbridge court. then turn left and go for a little bit. you will see a guy in a woodcutting skillcape. near some trees. talk to him and you can get the woodcutting skillcape for 10k from him.
It depends on the average hours you spend wc'ing a day.
There are some online Runescape skill calculators that can help you calculate that. Search for one of those.