Besides the men of steel riding horses of iron (M/Cs) - 
there's folks who ride hay burners, rather than gas/diesel burners!
.........Equestrians..:W
Another ERS option, see - 
US Rider ERS Yes - it's intended (but not limited) to/for folks who tow trailers with horses.
Click the "FAQs" - and read very - 
thoroughly -and- carefully!.
As pertains to "no coverage" by AAA in certain areas, see:
What if US Rider cannot locate a service provider to help me?
Will US Rider cover me when I tow my 
non-horse trailer?
Will you cover me if I am towing my horse trailer with my Motor Home?
(Note:  "We will cover our members in any non-commercial vehicle they are traveling in.")
Does US Rider have coverage in my area?
(Note: "We pay the Service Providers 
going rate and are free to go outside our network at any time to provide members with the quickest response time".)
The rationale for excellent *quality* service should be obvious:
Expensive, live animals.  Heavy trailers often with living quarters and accommodations for more than one horse & tack.
("Normal" tow operators will *not* tow trailers with horses.)
:B
~