Just returned from 5 days there yesterday. Very,very crowded! Lots of traffic and no parking. Attendance this year had exceeded their busiest year ever a week ago. Book a yellow bus tour if you can. They were sold out for us. A boat tour on Lake Yellowstone is also nice. Again you must book in advance. The road closure between Lake Yellowstone and Lamar makes for a very long trip around through Mammoth. 3 hours or so each way. May be longer if you encounter a bison jam!
Very limited dine in options available. I waited in line 2 and a half hours for a table at the Old Faithful Inn. The Lake Hotel Dining room is only available for hotel guests and sold out for the year.You can get on a waiting list but that closes down very fast. If you are staying in the Hotel itself you can dine in for breakfast if you are early.
All other dining in the park was carry out. All had long lines.
Also very smokey due to wild fires in Idaho and Montana.