It would have been prudent to answer these questions before you spent 5 years and $65,000.

Ask the registration authority what you need for registration. The rules vary from state to state, but it is almost certain that you will need a gas certificate and an electrical certificate and probably an engineers certificate. That might be difficult if you have not consulted these people up to now. The gas and electrical installations will need to have been completed by licensed trades people who should also provide the certificates. The engineer needs to be approved by the registration authority. You may need to shop around and it might cost quite a bit because the engineer will not be able to see stuff that is under the "skin".
If you want the registration to be in Queensland it is likely you will need to do all of this in Queensland.

For the insurance, start by getting a valuation of the vehicle by a person approved to do this by the insurer you are contemplating using. Ring a few and they will provide names of who they accept to do this.
Cheers,
Peter