Rabaul Tour

We'll be in Rabaul on 12th March and want to visit the volcano observatory, hot springs and, to a lesser degree, the barge tunnel. With cruise lines using a 150% markup on wholesale half day trip prices, I tried to find an independent trip. However, there appears to be a bit of a monopoly with local companies quoting even higher prices.

Can anyone tell me whether there are likely to be cars/minibuses with drivers at the landing point that would offer reasonable prices for 2 or 4 people, either as a small group or as part of a bigger group?

We were there in November 2013. I think most of the vans and guides where taken up doing the P and O tours. I did the morning tour which was excellent but was running late returning. Which made the afternoon tours to be cut short and miss out on the volcano observatory. I did talk to some people who took a local tour to Kopoko. It was really super hot and the highlight was the volcano erupting as we left the harbour.