> whole repair job cost me $450 at half price
> Does this sound resonable and fair to you guys?

Probably, although the nice folks at AA Transaxle will sell you a rebuilt 
tranny with the 3/4 slider bugfix and a 3 year, unlimited-mile warranty for 
around $900, so I'm not sure if I'd pump any more cash into that one if you 
have further problems.
Regarding your fridge question: if I recall correctly, you can run it off 
12VDC whilst driving, but there's something weird about it: no temperature 
control while on battery or something like that.