The rules for riding horses are unclear. There's a brief description of what the 'ride' skill does, but then it refers you to another section that is supposed to tell you more but doesn't! At least, as far as I can see.
Based on the description of 'ride,' the skill lets you do things like mount/dismount unaided, gallop, and do other more dangerous stuff without having to take a risk test (50% chance of damage). So I'm going to assume you can ride horses at a moderate pace without the skill, though you might fall off occasionally.
Max doesn't have the skill either and I've let him ride a horse.
Anyone who's done a few days of riding can pay 100 EXP to learn the skill if they want!
Julian can drive a coach or cart/wagon (or chariot!). But you'd travel more slowly than you would on horses. On the plus side, you could carry some trade goods if you had a wagon.