I found an excellent mod that allows followers to ride their own horse and to say it works beautifully is an understatement.
Horse For Followers
There are a couple of mods like this but I tried this one first and I cannot say enough how much I'm loving it. I wish Bethesda had done something like this for followers at the very least.
Mind you there are a lot of comments where people are having problems but it may be other follower packages or something else. I have no idea really. All I know is it works for me. I purchased my first horse at the same time as Marcurio's from the stables at Whiterun via the dialogue options and it worked. I also don't have any other mods that affect followers or horses except Essential Horses and I don't plan to use different followers, at least for this character and she's my only one at the moment since i got my game working properly.
I must admit I've only used it so far with Marcurio, but he's well and truly got the idea. But, I can't see why other followers shouldn't be the same as their packages should be basically similar, except maybe for the House Carls like Lydia, who I don't use as her comments annoy me. Not only does Marcurio mount when I do, but he dismounts when an enemy is near and attacks them. If I remount my horse and ride off leaving him to find his horse, he does so, no matter how far back it is and catches up to me. It's like it was already in the game.
I just wish I could do a quick dismount myself instead of the awkward almost fall off my horse animation, and sometimes having to mash the E key to get off when I'm ambushed. The only thing about this mod and it's not a complaint...is the author, Jorne, made the horses run away a short distance when danger approaches, whereas my horse runs in like a kamikaze. Sometimes we have to find his horse, especially if we're in a wooded area...and mine as well since they don't have a location marker. However, as I said, I've taken to just mounting up and moving on and he finds his horse without any problems.
This is a better pic of my character Sonje. She's a Nord, a light armour, sword and shield warrior.and I have Marcurio as ranged backup. Sooner or later I'm going to do some writing and outline some characters and adventure stories which I'll post here.
These next two screen shots are of Draugr using weapons from RealSwords Nord which is soon for release.
Shingouki is doing a great job of getting these weapons in game and the other racial blades will follow later.
Poor Farkas. I did heal him after although he's essential for this quest. Just makes me feel better...lol.