Hi there,
I've been involved in formal/informal EPO (education & public outreach) on space/spaceflight for more than 25 years! Right now, I figure we're looking at probably at least a 25-30 year time-frame before we have a "manned" flight to Mars -- in fact, it will probably be a mixed gender crew, both female and male astronauts, and not necessarily from only the United States, but most likely from major space-going nations, like U.S., Russia, Japan, Canada, member states of the European Space Agency (ESA), and possibly China by then, who knows...?
Round trip, well, that depends on how long they'd want to stay on the surface, but anywhere from 1 year, or 2 years potentially, round trip. The International Space Station orbiting Earth is but one small step towards a landing on Mars. Keep a positive thought though, perhaps that astonaut could be you, or someone you know today! We explore Mars today with roving robots like Curiosity, it's BIG, about the size of a "Smart Car"! To see more on it, visit this site:
www,jpl.nasa.gov