As a kid I lived on Long Island.
I had my horses at a family friends home.
I did all the care myself and we kept the horse trailer there too.
As a young adult my then show horses were boarded at a barn where I took lessons and showed from...our trailer was then kept on site locked tight so no one "borrowed" it without permission.
As a older young adult I worked the barns and kept my horse where I worked...and my trailer was kept on site too.
The most I traveled was about 1/2 hour to get to the barn but many traveled a hour or more if you wanted to ride with a particular trainer or barn was very common...
As a barn worker, I traveled to different jobs sometimes 1 1/2 hours not because of distance but because of traffic congestion making travel slow...
When a paycheck is a incentive to make good money you will drive...
As a adult, today I live in Central Florida.
My horses are in my backyard as are my trailers....
Depending upon where you live you might need to travel easily a hour or more to ride with good instruction.
Most barns here have trailer parking space and live-on-the-grounds owners or barn help so a safe environment to keep a trailer is very possible.
With the amount of trailers and horses along with livestock here unless you have a extraordinary trailer to my knowledge no one messes with what is a common commodity.
From very rusted old to the newest of top-of-the-line you see all kinds and values on the road and in yards.
I'm sure there is a need for places to store trailers, but there are storage facilities in many communities now that have vehicle rental space as I see campers, horse trailers, boats and boat trailers and all kinds of enclosed trailers in my travels behind commercial height fence with guarded entries and security codes needed to gain entrance to those facilities.
Is there a need for storage, sure
but it is
available, easily found too..