A retired couple can both draw SS and approximately 20K of other income and pay no (or little) income tax. For the average couple, that translates into about $48,000 of net annual income with no income tax. To the extent you need more than that to fund your retirement, taxes kick in albeit at low rates initially. At some point SS becomes partially taxable.
It is advisable to wait until 65+ to draw Social Security if at all possible. (Your benefit amount will be severely cut at 62).
We don't find life on the road that expensive. We budget and find savings at places we can camp free or inexpensively. Food is the same. The RV is paid for. We are not retired, but are "practicing".
The one good thing about the ACA is that folks like you who want to retire pre-65, can be assured of buying coverage regardless of your pre-existing conditions. Depending on your income, you may even qualify for a subsidy. Health insurance is the wild card when you retire pre-65.
Look for a tax guy who can help you crunch the numbers and keep you on track. A little planning goes a long way. Check out naea.org. We are all licensed and dedicated to our profession.