hello thorny
we purchased a compact graco pack n play that fit perfectly in between our twin beds. Sorry I can't find a link for it but it is called "compact pack and play".
there is also a longer "traveller's cot" made by "phil and ted", it also fits in between the twins if you turn the feet in. (fits in a 1998 at least - not sure about 2009)
philandteds.com - sleep - traveller
5 kids - wow!!! we just have one and feel like we use every inch of our 34 footer. Your airstream sounds like it will be a lot of fun!
we also found this handy for the picnic table. it folds down for travel:
Amazon.com: Chicco Deluxe Hook-On High Chair - Nature Pattern: Baby
hope you can get the hammocks figured out! happy travels!!
