Being a 1957, this should be a Dominator 99 (someone correct me if I'm wrong). It was a 600cc parallel twin housed in the famous "Featherbed" frame, generally regarded as one of, if not the best handling of its day. It was so good, as a matter of fact, that many riders mounted other makes of motors in the Featherbed, creating some very interesting motorcycles. So, yes, if any motorcycle of that day were ever up to being ridden in this fashion, the Dominator certainly is.
Here is a pic of a representative example. Not his, but one just like his:
Classic combination, a "Triton", Triumph motor in the Featherbed frame:
Or, how about a "Harton", a Sportster motor in a Featherbed:
