The United States is very large, and every time you go somewhere it's different. This summer, I went to Yellowstone and chose an SUV, but I regretted it because the high center of gravity made it tilt heavily on the mountain roads... and all the roads were paved, so if you don't have a need for a lot of luggage, don't choose an SUV. Last year, I rented a BMW 4 Series to drive around the Grand Canyon area and it felt great. I stayed in Yellowstone for 5 days, 2 days at Old Faithful, 2 days at Canyon, and 1 day at Yellowstone Lake. The itinerary was not tight, so I just played around and drove all the roads in Yellowstone. Accommodation in Yellowstone is expensive, and the itinerary was not optimized, but the gas prices were cheaper than in the Bay Area. As for cash and credit cards, to be honest, I haven't used much cash in recent years. I only keep cash for tips. Throughout the trip, I only used cash once at a strange restaurant in Salt Lake City for one night, and also used cash to send postcards at the Yellowstone post office. Everything else was done with credit cards, including self-service gas and meals. It was surprising to find out at a gas station in Carson City that they explicitly did not accept VISA credit cards and had to use a MasterCard. I remembered trying credit cards at gas stations in Utah and San Diego last year, and this year's experience was really different, as many gas stations have upgraded ?
United States Q&A