I can only tell you about my experience looking for horse people to rent my 2B 2Ba, w/ attached garage, two-three stall barn with a big loft, and 15-ish acres of field, seven or so fenced. I would put up a run-in if it meant getting solid horse-owning tenants.
Since I left Maine in the fall of 2015, I’ve had five tenants.
Two horse households – one needed a spot after they sold their house while they built their own barn; one moved back to Cape Cod; one alpaca farmer couple – had to send them packing because they were illegally AirBnB-ing & HipCamp-ing my property; one organic farmer family who found their own place nearby.
My current tenants are not horse-y. They’re building a home and leaving soon, so I am in mid-debate whether to look harder for people who would use the barn etc., move back myself, or rent to normies again.
Long story short, anyone like me who wants to rent their horse property would generally like to have their facilities used, so mowing, maintenance, etc. at least get observed if not accomplished. That almost certainly means a year-round rental. I’ve found that people who can afford to shift their operations seasonally also can afford to buy a summer place of their own.
That said, lots of boarding barns in New England lose clients in the summer because a portion of their boarders have horse facilities, but aren’t mad crazy about tending after horses in the winter. You might find reasonable shorter-term boarding situations in a cooler clime and be able to pick from lots of options in the human summer rental department.