In the television show "The Expanse", we see the Solar System having been partially colonized and developed during the 23rd century. The spacecraft in the show appear to depend on conventional chemical rocket engines (or possibly a much more efficient high-thrust ion drive). Ceres has been colonized as a primary station within the asteroid belt and various spacecraft are depicted as hauling ice from other parts of the Solar System. In particular, we see an "ice hauler" spacecraft in orbit around Saturn which then departs to return to Ceres.
Although there has not been any explicit timeline shown, it is essentially implied that this type of mission is commonplace and simply a way of life for many of the colonists (known as "belters"). However, considering the expected trajectories for transferring between Ceres and places such as Saturn, I would have thought that it would be unrealistic to expect a crew to commit to this kind of lifestyle -- most importantly the time it takes to go back and forth between those two locations (or others).
A Hohmann transfer from Ceres to Saturn would take about 7.64 years (one-way) at a minimum Delta-V of about 7.57 km/s, but you can reduce that duration immensely at the cost of more fuel by transferring with higher-energy trajectories. Here is a plot of the one-way transfer time as a function of Delta-V:
Note that a Delta-V above 19 km/s corresponds to an escape trajectory from the Solar System.
And here is a look at the family of trajectories -- each rendezvous with Saturn occurs at the same anomaly location, whereas the departure anomaly from Ceres varies. I'm assuming that Saturn and Ceres are in circular orbits (they have eccentricities of about 0.055 and 0.075, respectively), and that they are coplanar (Ceres is at about 7.5 degree inclination compared to Saturn, so that is not insignificant but neglected anyway).
So what we see here is that a mission from Ceres to Saturn and back would take somewhere between about at least 4 years and at most about 15 years. Clearly there are careers on Earth that take people away from their homes and families for a year or two at a time, but the travel time for these missions does not seem like something that would be undertaken as a career choice. Does this suggest that the kind of rough-and-tumble crewed space mining concepts are unrealistic?
This question is rather broad, so I'll say that answers should really focus on (a) the elements of propulsion and orbital mechanics that define how long these transfers would take, and (b) what kind of outlook we might expect for manned spaceflight as a career (probably most comparable to tours in the military or jobs at sea).