To wrap up a few questions and loose threads.
Electrical power. We need an Energizer Bunny on steroids. One way of doing this is to have powerful magnetic coils surrounding a flow of plasma. The rocket exhaust is plasma. So a percentage of our thrust could be sacrificed to draw power.
We won't be thrusting ALL the time folks. We really don't need 100 years of continuous thrust. 100 thrust-days should do it. Remember, 1 [ONE] thrust-day gives us a delta-V of between 150,000 and 200,000 MPH. 3 thrust-days should push us well over 500,000 MPH, we cruise unpowered to Jupiter in 6 months, and 3 thrust-days to decellerate into orbit. Is that good enough??
What about power when we are not thrusting? We need a nuclear thermal reactor. It will have to be shielded. Sorry. I'm gamma intolerant, and if you don't shield the reactor, I won't be able to go.

{sniff} Fortunately, a 5 megawatt reactor core should only be the size of a volkswagon bus. It should be mounted on the nose of our ship like a loooooong radio antenna boom, with generators, reactor and a disk-like shield way out in front, well away from protoplasm.
Or we can use balonium, which is as light as parafin wax and will stop any radiation.
Changing course is gonna be a bitch. Sorry. The rotating hab-pods, you know. Have you ever put a bicycle wheel on a ten-inch axle--hold the axle with by either end--spun the wheel up real fast--and tried to change the pointing direction of the axle???

It is incredibly difficult--and the axle wants to move at right angles to the force you are exerting. Lotsa fun.
So, we must assume we de-spin the ship for flip-overs and all other course corrections. I'm fulla bad news today. Oh, well, just say that the crew gets two days of zero gee for recreation and amusement.
We could "store" unused electrical power by separating water into H2 and O2, then recombine as need to supply power and water.
How do we get the goshawful goddammerungen specific impulse (fuel efficiency) we need to keep our fuel ratio down below 20%-40%??? Using it for heat is not good enough. We need the efficiency we get in a tamper & implosion squeeze device.
I have one word for you: lasers. The fuel is powdered, mixed well, and coated in plastic. Each grain of powder is uniformly coated. Many large tanks of powder, shielded with balonium. The grains are individually ionized, shot down an electric rail-gun, and as it enters one of the firing chambers, a 1 nanosecond burst of laser light from all sides hits the grain, vaporizing the plastic explosively, and squeezing the powder grain down to half its normal volume. KABOOM! 1 ton equivalent high explosives. Just off the top of my ass, we need to burn maybe 1,000 grains per second. Easy sneezy. Half our thrust goes to power the lasers and refill our H2/O2 tanks.
That's all I can think of for now.