I have and vote for the Krait Phantom as an exploration ship as well. I've equipped it with everything I need for exploration (minus a Guardian FSD Booster because I've not unlocked that yet), done some engineering (not done yet, some engineers I'm still unlocking) and added the FSD Engineered v1 (you can get it from a Human Tech Broker), I get 55ly - 60ly range. It's ~84 million Cr with 4.2 million Cr in insurance. Oh and the resting heat is low, so you can make a jump close to a star if needed, or turn on silent running as part of an FSD cooldown if your shields have failed for at least some time.
Build specs:
https://s.orbis.zone/dqml
Notes:
1. You can't select the FSD Engineered v1 in Coriolis which adds 15% more Optimal Mass so the jump rang is higher than Coriolis shows.
2. I have one or both AFMU(s) disabled unless I need to use them to save power.
3. For longer trips I will unmount and store the guns, mostly they are there for travel inside the Bubble to annoying anyone trying to shoot me until FSD cooldown and I can high-wake out.
4. If you want a little extra power you can do more engineering on the Power Plant or go up to a 5A, or even strip a few things/do more power management and get down to a 3A Power Plant, but that's cutting it very close to redline (especially if you swap something for a Guardian FSD Booster) and you'd really need to consider if you want to run that close for a 1.98t (0.29ly) difference.
5. You can drop the Shield down to a 3D, but rough landings and escaping from a conflict are more difficult to do without damage.
The only real must for engineering is the FSD, unless you purchase the one from the Tech Broker, and Farseer can do that all the way to G5 - along with a number of other items in the list at lower levels.
While a Python can be used as well, it's heavier (Krait Phantom 270t hull vs. Python at 350t hull) and I don't need the extra slots (not that both a Guardian FSD Booster and an extra AFMU wouldn't be nice, but it's not worth it to me), so that's 80t of mass right off the bat you've saved.
Good luck!