Yes every state is different for insurance as well as registration transfer issues.
IMO if you bothered doing the VT rego, next step is getting it insured as is.
Get a referral from Kelly Newsome at the Knowles Allstate office in Leesburg, 352-326-9300
Then the question is, A what is your state's requirement for getting locally registered before X days "garaged" in state
and B do your local LEOs enforce that?
The goal is to get your conversion work done so you can then pass inspection or whatever is required to get the rego category you want.
If you have private land and keep the vehicle out of site
except when occasional travel is necessary to get work done
you might be fine keeping the VT rego for a year or more.
Or if you are planning on going interstate, living as a nomad, you're definitely able to keep it indefinitely, so long as you avoid visiting Vermont, when you would need to pass **their** inspection.
TL;DR it depends