[quote=@Bishop]
[@natsucool] I'm assuming you planted the lance, not wanting to post twice. I will edit it though if you have any objection.
[/quote]

There is no tree inside the cave <_> so your wires technically wouldn't work.
The boat if you recall, is inside the cave itself. Once you drop the coin in, you can pass the barrier at the mouth of the cave which would have normally kept you out. However the coin only allows you into the atrium of Hell, not the actual layers, for that you need a boat.