I have problems with the "crawl tubes" in a museum's atmosphere; unless it is geared towards a children's exhibit.  If it is just a recreational item, then I feel that it will deter people from the rest of the exhibits, including the children's.  Our goal as museums is to educate, in a fun and exciting way. I don't see the educational atmosphere enhanced with a "plain" crawl tube.  I guess your main question should be, how can I incorporate crawl tubes, without detracting from the exhibits?  

The second thing with crawl tubes is insurance.   You now have to worry about children getting hurt within the tunnels.  It is important to develop children's interests, but to might become dangerous.

Finally, these crawl tubes will not be handicapped accessible, which cuts an audience out of its enjoyment.  If it is an children's exhibit it should be in someway accessible to all.  I am not saying for you not to do the crawl tubes, but to think how you are going use them

Edward Sakowicz