Crunching mission time.

So with orbital manoeuvring and transferring of fleets and the like, it would be really useful to have a clear cut method of figuring out how damn long something will take to get from a to b. Now i know it is obviously more complicated, but others here seem to have done it so here is my basic question: I want to get some system for calculating mission times based on Dv input, others have made claims like "with the new MPD thrusters it could get from Earth to Saturn in Six months" but how do you get to these results? I am familiar with calculating Hohmann transfers, but most of the guides i use assume a traditional probe mission, not a GW-roid raging Ion drive ship. Do we even Use Hohmann  calculations for a continuous thrust model? Without the drift phase gone does it not become a traditional ballistic method? This is of course using average orbital measurements without also going into the nightmare of year 21XX planetary cartography and orbital positions.  

So in other words is their some system like:

INPUT:                                                                OUTPUT:

                                                                                TIME TO TARGET WITH A)CONSTANT BURN AND DE ACCELERATION B)WITH  BURN TO HALF FULL COAST
                                                                                                            INJECTION WITH REMAINING HALF C) WITH MINIMUM TIME WITH MINIMUM BURN
Dv
ISP
DRY MASS
WET MASS
STARTING TIME
BODY A
RADIUS
MASS
INCLINATION
ORBITAL PERIOD
ARGUMENT OF PERIAPSIS
LONGITUDE OF THE ASCENDING NODE 
BODY B 
RADIUS
MASS
INCLINATION
ORBITAL PERIOD
ARGUMENT OF PERIAPSIS
LONGITUDE OF THE ASCENDING NODE