Those two questions are incredibly difficult and complex. That being said, the first one we have more data.
The New York Times/UpShot has been running a very useful tool (links are at the bottom of this post) to project delegates going forward. We will first start at the Democratic side.
This Tuesday, we have only one race with a closed primary. This is Arizona. Arizona has the largest delegate prize of the day. While all Democratic races are proportional, a win here for Clinton could negate a win for Sanders in Utah and Idaho. Therefore, the best case scenario for Sanders appears to be roughly maintaining his current delegate deficit coming out of Tuesday. The scenario will put him even further behind when it comes to the percentage of the vote Sanders will need to win in all future contests after Tuesday. At this point, he can't settle for beating his polling from 6-12 months ago. He needs to start winning states by large margins to even have a shot at the nomination.
Mathematically, I see no path forward for Sanders. Sanders could win all future states by 57-43. That is the margin Clinton has won all previous states at on average. In this scenario, Clinton will still win the nomination. This is based solely on pledged delegates and not on PLEO's. (super/unpledged delegates)