I just listed them to show size. I could see using the 10,000 btu only because it has the ability to bring in fresh air which the 8,000 btu one doesn't. If you're bringing in fresh air then you would likely need the extra if you in a hot area. If you inside with 2 people and 2 large dogs the fresh air and 10,000 btu would be very useful.
The ones I was looking, both 8K and 10K, at have electronic controls and a remote. You can then place the remote on the wall so you don't have to get on the floor to make adjustments.
Edit: Humans put out between 300 to 600 btu/hr and large doge, 75 lb. and up, puts out close to the same. Using the mid point of 400 that's 1,600 btus/hr. Now add in anything else you have turned on plus what the trailer absorbs.
BTW, a Civic AC is over 12K and a small SUV more likely 24 to 30K. True they don't have a lot of insulation but when you think about it 8 to 10K is not that much.