Hard to say on the loan. Most, but not all, prefer not to loan on a coach over 10 years old. You'll need to ask around. The lenders look at an older coach as a bit higher risk that you might default on it. As such if you do find a lender the interest rate might be a couple of percentage points higher and/or require a substantial down payment.
Considering the uniqueness of a Newell I would give them a call directly (1-888-3NEWELL (1-888-363-9355))and ask the sales staff. They might have lenders that understand what a Newell is a bit more than a box of wheels.
Concerning insurance - worst case scenario Lloyds of London will insure anything. Weren't there a couple of actresses that insure their legs in the 1950s-60s with Lloyds?
2006 Hurricane 31D built on a 2006 Ford F53