1. I've never gone in through Wentworth entrance.
2. It sure is.
3. Tough question to answer as there will definitely be traffic, and different people break different stuff every time. Breakage can cause some serious delays on the trail. With a good pace, I'd say 5 hours to the Springs from Loon. I usually break it up though and take my time to get there. After Rubicon Springs, Cadillac Hill is the only thing left until you're out, then it's a pretty long, dusty, rough road until you get back to civilization. I'd say roughly an hour and a half.
4. The only part where it really smooths out is right before you get to Rubicon Springs, but it's best to still take it slow to keep dust down, and simply out of respect for the trail and others.
It's an awesome trail, and as much as you try to plan your weekend out, unexpected stuff will always seem to happen.
