Been working with one of the busiest surgeons for about three years now at one of the largest public hospitals in my state start up his research effort that is highly benchwork based (he came out of residency maybe 5-6 years ago). Long story short, it's difficult. Incredibly busy clinical schedule and always on-call so essentially i've been on my own for three years now (even since I was an undergraduate). Writing grants, formulating contracts, administering protocols, building a reliable team, etc all takes a lot of time. Can it be done? Yes. But is it difficult? HELL YES.
But with that said, I've also had the pleasure of working with a number of amazing physician scientists with well established labs in my time as a research coordinator. Surgeons doing all kinds of stem cell and regenerative medicine research and/or molecular biology research. It's really quite amazing to see them balance it, but nonetheless, it can be done!