Do old faithful in the morning. We visited on the 4th of July weekend, busiest day of the year, again, if you enter
Before 6 and hit old faithful early you'll miss the crowds and have time to enjoy the rest.
Wait until 8am or later and your are looking at hours to get to the loop road.
It's not ideal to go on busy weekends, but you can survive if you go early to the touristy parts.