We have a global system for fission, and fission actually covers a wide range of possible fuels, not just uranium and plutonium that we currently mainly use. Its a known quantity. You can call up and get a dozen quotes from people with proven experience. We know about the wastes and the fuels and how to integrate it. Fission had a lot of help with subsidies from national nuclear weapon programs, defense, etc.
If we commissioned our first commercial energy fusion reactor today, it would still take decades to sort all this out, to work out all the radioactive products and how to recycle and reprocess, fixed costs for commissioning and decommissioning a reactor etc. Fusion isn't totally clean, you get neutrons, neutrons hit things and all of a sudden everything changes, things that weren't radioactive become radioactive. Neutrons themselves are of course a type of radiation that needs to be shielded. So apart from fuel costs, running costs of a Fusion reactor might be considerably more than a nice simple refined Fission reactor.
While I think fusion is more promising now than its been in the past 20 years its still a whole new animal. It won't be cheap for a long time. It won't be small for a considerably longer time.
With electric drive you don't really have to settle on anything though, Diesel, nuclear (fission or fusion), battery, or any variation thereof.