Don’t get within 100 yards of a wolf or bear, or within 25 yards of bison, elk, bighorn sheep, deer, moose and coyotes. Rangers say more people are hurt by bison than by bears. (Bison can run about 35 mph, three times faster than most people.)
Don’t imagine you can cover 20 miles in 20 minutes on Grand Loop Road, the park’s main artery, which is shaped like a big figure eight. It’s mostly a two-lane road, with speeds capped at 45 mph or less. Animals frequently interrupt traffic.
Don’t expect easy winter access. Most park roads are closed to automobiles between early November and late April, and most park lodgings have similar seasons. But there are winter lodging options (yellowstonenationalparklodges.com).
Do brave the crowds to see Old Faithful spout. After all, it’s the park’s marquee attraction. And the people-watching is priceless.
Do check out the rest of the Upper Geyser Basin, a collection of about 150 geysers neighboring the Firehole River. If you take a bridge across the river, the features continue, connected by a boardwalk and trail.
Do book at least six months ahead, especially if you want to stay at Old Faithful Inn, and forget about staying there in winter; it’s open only in warmer months. (It closes this year on Oct. 11.) It’s an easy stroll from dozens of geysers. Rooms for two start at $108 (for old-style units that share a bathroom down the hall) and go up to $260. Suites fetch $479-$525. For info, call Xanterra at 1-866-439-7375 or go to yellowstonenationalparklodges.com.
Do get to Midway Geyser Basin by 9 a.m. That way, the parking lot might not be full yet. The main attraction is Grand Prismatic Spring.
do take the Brink of the Lower Falls trail along the Grand Canyon of the Yellowstone River, if you’re in decent shape. The trail of switchbacks down to the falls is only 3/8 mile long, but it’s a 600-foot altitude change, which makes for slow going on the way up.
do head to Mammoth Hot Springs near the park’s northern boundary for nearly certain elk sightings. Mammoth Hot Spring Hotel & Cabins will be open through Oct. 12 and in winter from Dec. 18 to Feb. 29. But with upgrades in the next several years, Xanterra hopes to make this the only park hotel open year-round. Rooms $90 to $250; $479 for suites. Info: yellowstone nationalparklodges.com.