I intend no disrespect, but from your comments I sense you have not spent time as a working professional pilot. Your intentions may be honorable, but in the working pilot world you will create a bad reputation for yourself by buying a type rating a working for free.
I applaud your desire to fly during retirement but please stop saying you'll do it for no pay. Honestly, among good operators, if you say that during an interview your resume will be sent to the bottom of the trash can. Good flight departments do not want seat fillers who are willing to fly for free.
OTOH, there are plenty of cheapskate Pt 91 operators who will happily not pay you, but I personally would not want to share a cockpit with them. In my own career, I've come across a number of folks who have said they'd fly for free and they have garnered bad reputations and quickly disappear. Please don't do it.
On a side note, you should never, ever, ever pay for your first type rating. Unless you are flying your own, personal aircraft, an employer should pay for training. A type rating is required for acting as PIC. No one in their right mind would hire you as PIC with a fresh type-rating and no time in type. You can be SIC on any aircraft the PIC is willing to have you, even single-pilot aircraft.
The best way to go about progressing in the career (at any age) is to offer yourself as willing to toss bags, pull gear and handle the radio for a reasonable day rate. This is also called "squawk and talk" and "gear up, shut up". Airplane operators to target would be those flying single pilot aircraft: PC12, any King Air, Citations and CJ's, etc.