[VAC] A/C, swamp cooler and/or fan recommendations to replace carnk-up vent?

[Wayne <wayne2@xxxxxxxx>]

Two questions:

I am considering replacing my crank up vent with one of the following:

-Duo-Therm Penguin rooftop air
  -is it true that it doesn't require any add'l. holes and that it's 
captured to the roof insid the 14x14 inch hole? I'd like not putting 
more holes in my vintage aluminum if at all possible.

-Some kind of evaporative cooler
  -anyone have specific recommendations for a rooftop unit that would 
mount into a fan hole?

-Some kind of {Fantastic, MaxxAir} Fan just to move the air around... 
stale air in a hot trailer is a kind of a cruel and unusual 
punishment that I'm not up for anymore.


The trailer is approximate 725 cubic feet (16x7x6.5)

I am looking for sources for the best prices on each of them if 
anyone's got leads...

thanks,

wayne