Question:
I have seen people put a fan in the window pointing towards the outside with the idea it pulls the hot air out.

Reply:
Quite frankly if you try this you will get minimal results.
You would be better off opening all the windows and doors in the house and blowing the fan onto you.
Buy an air conditioner if you really want some relief. It is better to be able to cool down 1 room and be comfortable than playing with fans and windows etc.

Question:

I have a really small cabin that I use a portable air conditioner. It works good until the temps outside rise above 90 degrees. Anything in the 100′s, or 110, it can’ tkeep up. I live in a VERY dry climate with < 10% humidity. I was thinking of also getting a portable evaporative cooler and running them both at the same time. Do you think there would be any benefit? I would like to add some humidity to the air anyway..

Reply:

Without going into a lot of detail the short answer is no. Evaporative cooling and refrigerated cooling working in the same environment do not work. The 2 types of cooling do effectively cancel themselves out.
If you do have a humidity problem and wish to cool your cabin you should invest in a dedicated humidifier that supplies the required humidity and can also be regulated according to your settings.
Sounds also that you need to upgrade to an A/C unit that will do the job. My advice is to buy a unit that will perform better in high temperatures conditions, have a heat load calculation carried out on your premises, they are usually given free with a quote for a new unit.
FYI: The industrial computer rooms of the past have struggled with this conundrum for many years and found the only solution to be as I have stated above or installed A/C units that have built in humidification systems.
Hope this helps.