Crowded Roads Revisited is the least buggy more optimized version of Crowded Roads, as far as I can tell. I really want to try out Immersive Travellers, though. I have not used any of the Crowded Roads mods. The concept was not appealing enough for me, especially in the face of a possible performance tradeoff. Tamriel Travelers have been the only travelers I need to see on the road. Plus, FCOM add pilgrims and all that too.
I have one on the Nexus called Friendly Fire for Frans that adds the chance of travelers appearing at road spawns, and also adds Alchemists, Woodsmen, and Hunters to the wilderness spawns as well. I find it has just the right number of NPCs wandering around, not too many but the roads no longer seem as barren anymore. Another good mod to get for road travel is Kuertee's Wandering Encounters. With that one, any Bandits and other intelligent creatures will sometimes start to travel to a random location in the world, sometimes a city, sometimes a dungeon door. I had one Bandit follow me into Anvil once, which was kind of cool. It took me completely by surprise when this battle broke out with the town guards.