I've been on vacation and travelling, so late to the thread. Here are a few comments, feel free to ask specific questions:
1. West coast to Australia is easy. Two options - Dockwise ex: Costa Rica once a year. Or deck cargo on the scheduled monthly service Swire runs. The latter starts in Vancouver, BC and stops at various lumber ports in WA and OR before calling at Los Angeles. It then hops the Pacific to Brisbane and Tauranga, but can stop at some of the South Pacific Islands. Steel is the main return freight. If you use this type of service it is likely worthwhile to use a shipping broker to manage stuff like cradle, port services and customs. I used Aurora Global Logistics and they did a really good job.
2. 230V / 50 Hz. I agree with TT in that ideally you want boat to have native voltage in your home port. But Brian Harward highlights that you can certainly do it differently. As a first step I would make an inventory of all the AC gear on board. Then choose your path. You might find, like me, that many items can run on 12V DC often with lower power consumption overall than if they run on AC. In the overall scheme of things it is likely not a big cost to ditch the 120V/60Hz items. I have both 120V and 230 V receptacles on board, but do not have many 120V appliances left. I am using 2 Charles isolation transformers. One is doing what the name implies. The other is a step-down so that even with 230V shore power I can provide 115V to my legacy 120V switchpanel. But, it is at 50Hz. For my toaster and other resistive loads that is of no consequence. For inductive loads, washer and dryer in particular, it does overload them. In hot weather the dryer will shut off part way through the cycle due to overheating. My plan is to replace these items with 230V 50Hz appliances, I just have not done it yet. Things like the Insinkerator are specced for 60Hz but don't run long enough for 50Hz supply to be an issue, so far at least.
3 Converting the boat power. This is not a trivial undertaking at all. Here in Queensland the marine electrical stuff has stringent government regualtion. Only a licenced electrician can work on anything above 12V, and if he does then his arse is on the hook for everything on the boat. If there subsequently is an incident on the boat related to AC power he can be prosecuted. So the first time you bring a leccy on board he will have to satisfy himself about the standard of all the AC systems, not just the particular thing you asked him to work on. Cunning but shitty legislation! Knowing that I bought a copy of the Australia/New Zealand Standard (AS/NZS 3004.2:2008 ) and gave it to the electricians in Port Townsend who then ensured compliance of my new 230V switchpanel. That standard was updated in 2014, here is a link to where you can get it (at a cost unfortunately)
http://shop.standards.co.nz/catalog/3004.2:2014%28AS|NZS%29/scope?
If you are going to get the US manufacturer to do the conversion for you, then supply them with a copy of this Standard to guide them through it.
Likewise for gas (propane) there is a Standard. But basically even a new USA regulator, solenoid shutoff valve, supply line and appliances will not comply: they all need to have an Australia/New Zealand compliance number on them. Plan on having to replace the propane system entirely. Here you need a gas certificate (from a licensed person) to get the boat registered (mandatory), or to sell it. Fair enough, a poor propane system can cause explosions etc.
Getting back to your original checklist. Yes, US wiring gauge is heavier so has capacity for the 230V 50Hz loads. But the wire colour coding does not comply with our Standard, which is the same as Euro colour codes. A way around this is to buy appropriately coloured heat shrink tubing and slide long lengths of it over the incorrect wire colours where exposed at receptacles and at the switchpanel.
There is a whole bunch of other stuff I can likely give you tips for if you get to the point of doing it, happy to assist. None of the issues are insurmountable, but labour and materials cost do add up surprisingly quickly to 'fix' stuff that is perfectly serviceable in the USA.
