Best to have your OWN horse - then you can go where you want, when you want, and at whatever speed you want.
I lived in the saddle when I was a child. My horse was called Misty, and was a grey gelding. We galloped madly everywhere. Often I rode bareback. Sometimes we went swimming (horses can swim just fine).
I rode in the countryside, through the middle of towns, and along beaches. To get to the BEST beach I rode him onto the Sandbanks Ferry (Poole, Dorset, UK), and parked up in the middle of all the cars. The ferry journey only took 15 minutes. Then the cars started driving off, and Misty and I waited our turn. The we 'drove' off too.
Misty was very good. He didn't always stand still, but he never kicked any of the cars. Sadly, I see that the Sandbanks Ferry no longer allows you to RIDE a horse on. You have to have a horsebox!
Possibly I should start a discussion about the RESTRICTIONS and LACK of FREEDOM I feel in this modern world. When I was young I was bound by fewer rules. I rode ALONE for DAYS, camping out, and travelling forests and fields. I never wore riding gear or a hard hat, just jeans and a shirt. Lots of children rode off alone... and parents never worried (much!).
One of the reasons I'm travelling off around the world soon is to find a place where I have more freedom. England is too small an island for me now. The population pressure restricts me. The rule of the nanny state drives me nuts.
So, back to horses. Where to go? The Pampas of Argentina? The Mongolian steppes? The Canadian prairies? Where best to ride free and forever?
I rode horses at about age 12 in summer camp. We took the kids for a day of riding lessons in New Hampshire, some decades ago, when they were young teenagers and we were in our thirties. In both cases, of course, we were riding very docile horses.
The first thing is that horses shift their weight. And they will sort of bend over so that they can eat grass. It is not at all like sitting on a bicycle or motorcycle. It feels more like riding on your dad's shoulders when you were a little kid. It feels weird and insecure, and of course you are going over uneven ground and the horse adjusts to it instantly. It is like being in a boat on slightly choppy water. You have to trust the horse. They won't fall because they are leaning; they are leaning so that they don't fall.
The second thing is that horses do not steer mechanically, like a machine. You are giving them suggestions through the reins and they voluntarily obey.
At camp, I rode on horses that were walking and trotting. In trotting, you have to "post," which is hard to describe. You are kind of matching your up-and-down movements to the animal. If you ride a trotting horse without "posting," your rear end goes slap! slap! slap! against the saddle. It gets very uncomfortable very quickly.
I can't remember if I've ever gotten up the courage to ride a horse that is cantering. Horses have four different gaits, four different patterns of moving their legs: walking, trotting, cantering, and galloping.