Museum and boat trip to the geyser are completely acceptable from the price-performance ratio.
We would wish only a little more flexibility with the museum visit (U.a. after the boat trip to Geysir, so to speak a flex ticket). We would have liked to visit the museum more extensively before going on the ship to the geyser.
We accepted the shorter period only because we really wanted to see the geyser, since we were on the way back from vacation, are not regional residents and could come over at short notice.

The Internet also gave the museum lead time not so obvious. When booking tickets with a severely disabled child (GdB 80), the input is also not always so simple. In addition, we have the JuLeiCa (from Nds. comparable with the Ehrenamtscard) which is unfortunately still handled completely diversely in all federal states. The barefoot path Bad Sobernheim accepts it e.g. NRW Minden also...

Still, their museum is informative, kid friendly, the cafe and store is great!!!!