For immersion reasons, I never use fast travel, but I just had the brilliant idea that, since you can fast travel while riding a dragon, you can fast travel immersively by summoning a dragon and using bend will. Has no one else thought of this, or is my immense self-satisfaction at this revelation unfounded?
Makes sense to me.
Though, I don't see why fast traveling via carriage would be any different. Even in my RP runs, I do that some. After all, it's an in-world vehicle, no teleportation. Though I suppose you could make the argument that there's danger of bandits or something you are glossing over, which there wouldn't be on a dragon's back.
If you're trying to avoid skipping over the at-times rewarding process of crossing Skyrim on-foot, well, both methods get in the way of that.