On the topic of portable toilets, this the one that I use that I can store up in the luggage rack. I like the fact the legs fold into the unit, and the fact it's all plastic it can just be left out in the elements. It uses the W.A.G. bags with that chemical that absorbs liquids and then can be tossed in dumpsters or generally just buried. Takes up much less room this way. As I mentioned to somebody else off-line, sometimes the more important thing to me is an enclosure to keep the bugs away from me. Nothing like trying to do your business with 20 hungry mosquitoes after your derri�re. I have the porta privy made by outback for that, although I think that shelter that hangs over the hatch by the bus depot would be even better. When you haven't used the privy in a while, it can be an exercise in frustration trying to figure out how to fold that sucker up. 

http://www.campmor.com/reliance-fold-45-45-portable-toilet.shtml?source=CI&ci_sku=81044&ci_gpa=pla&ci_kw=

Troy