Myrtle Beach is nice so long as you are not there during peak tourism season.
I moved down there for the summer with my girlfriend from college many many moons ago during our summer break and the entire summer it was pathetic. There is a road and boardwalk that stretches the entire length of the beach, but it was so jammed full of college kids that driving was painful, you could seriously walk and get to your destination faster, imagine Mardi Gras but instead of drunk people wlaking the streets it's drunk people driving them, or rather attempting to.
The boardwalk was not much better. I didn't bike back then, but I do recall it being so full of people roller blading, biking, walking, pushing strollers, people pushing drugs, etc that it was easier to just walk the beach.
This is just my experience though, a little bit further south in Muriels Inlet it was much nicer though, which was kinda odd. You could say that Muriels was a suburb of Myrtle Beach but it was rarely full of people, kinda like once they hit the sign that said "Now Leaving Myrtle Beach" they turned around and headed back the other way because it wasn't "cool" to cruise any other spot. The beach was cleaner and the roads were tollerable there.