Your question fails to take the power of a nuclear pulse drive into account. The ORION nuclear pulse drive is the only high thrust/high ISP drive known to modern science, and theoretical calculations done back in the late 1950's and early 1960's, while the drive was under active investigation, suggested that 4000 ton spacecraft could be assembled on the ground and launched directly into space and on trajectories to Mars, and later the investigators hoped build ships to get to Saturn.
And this is with 1950 era technology....
Using Hohman transfer orbits is the means to get from place to place in the solar system using the minimum amount of energy, which makes sense when you are using a chemical rocket with far lower ISP, or a low thrust, high ISP drive like an ion thruster or light sail (this isn't strictly true, since after a while you will have built up an enormous velocity, but in practice you will be using thrust for weeks and months to build up that kind of velocity).
Are we there yet?
While ORION isn't exactly a torch drive (where you simply point at the planet you want to go to and blast away, flipping at the halfway point to decelerate), it does have more than enough performance to allow you to ignore Hohman transfer orbits. Perhaps the only reason you might need to do this in an ORION drive ship is you have depleted your reserve of nuclear pulse units, and need to drift on a minimum energy orbit back to base. Realistically, it would be easier for the base to send another ORION ship to you with fresh supplies.
This is the obligatory link to the Atomic Rockets page, which will help you conceptualize ORION and what exactly you can do with it. As a somewhat ridiculous aside, there is an even higher performance version of the ORION concept, called MEDUSA While this ship needs to be assembled in space, it theoretically will leave first generation ORION's in it's radioactive dust....
A visualization of the concept is here: