>  My new porta-potty lid is so thin, that I wouldn't dare step on it to go
> upstairs.

I have two--a Thetford and a another brand which seems to have
disappeared from the web.  I think Thetford is eating its competition.++

Anyway, I have used both as step stools to reach "upstairs" where
we store out gear at night.  They both can take 200 lbs easily.

re: strapping the thing down.  I never worried, until after the
aftermath of Roger's rollover in Wyoming last winter.  Then I
decided that I didn't want a flying loo.

I don't know what these are called, but as soon as I described
what I wanted, my local hardware store (McGukin's) knew.
You can see the hardware, how I strap the loo in, and a free
shot of one of my vinyl covers at
http://jones.colorado.edu/VW/potti

Enjoy--but not too much or you are weird....  ;-)

Richard

++PS: why two?  I bought a Thetford that would slide under
the seat/bed.  It is "small."  Later I bought the largest
size--too tall to fit under the bed.  The number of people
and the length of trip decides....