If you choose to work contractor the best way to handle health insurance is join some sort of group, so you can get group rates. And given your conditions choose the expensive options that give you the widest choice of provider. In Washington State if you've had coverage, they only let providers rate you on age not previous condition, which would keep costs within reason. Not sure all states have that rule, so you need to check regulations in whatever state you would live.
Chamber of commerce is the best deal for many people (so you pay the annual fee to be a chamber member, plus the monthly fee for your insurance, plus co-pays, deductibles and so on.)
Years ago the way to translate contract rates into rates for a company that provides benefits and pays employers portion of social security was to discount by 30% to 40%. Don't know what the formula today is, but maybe some HR people on board can say. At any rate I'm pretty sure you have to figure contractor payment is worth at least 35% less per hour than working as an employee. Benefits, tax status employer portion of FICA, unbillable hours - both for paperwork, and for stuff that you actually do for client that for various reasons you cannot bill.
And this asumes that you can get group health insurance that is purely age rated. Don't know whether some states can take existing condition into account when setting rates even if you have had no period without insurance.