Cross county by van.
My son is not retired but he essentially does what you want to do. He drives one of those pilot cars that accompany oversize loads. His vehicle is a Kia Sedona that we tricked out with a bed, storage and kitchen. He has been all over the country taking a week or so between jobs to explore. In November he spent a week at Joshua Tree NP and in January, he bought a pair of used cross county skis at a thrift shop in WI and spent a few days skiing in a state park.
You might be surprised but he cooks totally with electric. He uses an inverter and runs the car when he cooks. During the last redo of the van, we ditched the 2 burner propane stove and added a second battery. He uses this small 750 watt Japanese style cooker, plus a small single-burner butane stove for a back up.
I say go for it. It will be a great adventure. Do get a NP pass; mine paid for itself on the first trip out west.