The thing with the volcano
The tour the sends you on you own, you have a driver that takes you to the top to see the sun rise at about 5am Then they drop you off right outside the National park, there will be a lot of other riders there from other tours (some do have a guide, especially the little kid tours) . A good bike with front and rear brakes is needed. Also warm clothing and helmet, gloves. Also it is cool as heck in the morning. You actually do go down at your own pace, just drop off the bike when you get to the city. We stopped and had breakfast at a small cafe about half way down.
You actually don't ever have a guide, you kind of just have to know how to ride a bike and hit rear brake. Also watch out for Cows on the road.
I imagine if you rent bike, just go for the day rental. They find a driver that will take you to the drop off point. It better to ride in the morning.
Or if you find someone you know through here maybe they would help you out.
Man I saw the cost for the bike trip.
We went and sat through a hard sell time share for 1 hour. Got two tours, we got the turtles boat and the bike tour, the way to sit through the time share thing is get early in the morning. Keep saying no, get your free tours. It was a good vs playing 200$+ for some day adventures.