I did two US Opens at Oakmont, always Thursday/Friday. See a lot of players I might not see on the weekend, and the crowds were definitely manageable. Same with the year Tigers Tournament was held at Congressional.
Did a couple of Presidents Cup when it was at RTJ in Manassas. Practice rounds are the way to go, players are friendly, get to see them hit several shots (watched VJ hit a variety of cuts and draws with his 7 wood into a par 5 so he'd get a feel for the different pin positions)