Trump's yuge win last Tuesday makes it much harder to stop him and a win this Tuesday in Indiana would make it nearly impossible. For the Republicans, Indiana is winner take all, the last such primary this month for the GOP. (The Democrats are proportional all the way down the line.) Ted 'The Snake" Cruz is in second according to most polls, though there was one strange outlier that had him ahead by 16. The most likely result according to the polls is a Trump win by single digits, say about 7 or 8. I would not be surprised if Kasich throws in the towel later this week.
Hillary's lead over Sanders is more modest, probably in the 4 to 5 point range. It would certainly count as an upset if either of the front runners lost, a much bigger and more stinging loss if Trump gets beat. The rest of May is mostly Western states and not very large prizes, so barring some dramatic development, I'll probably wait until the big June 7th set of primaries, which is mainly a Western test (California, Montana, New Mexico, South Dakota) with New Jersey just to keep things strange.
Pundits are assuming it's Trump vs. Hillary, and I have no reason to say they are wrong, which is rare for me. Once that happens, it's a question of which party can close ranks the best and get out the vote, or in the case of the Republicans most effectively suppress the vote. This is not to say it looks like a toss-up, because Trump will be hard pressed to win any state Obama carried in 2012. It hardly counts as a prediction to say Trump will continue to be ill-informed and ill-mannered. If I am to go ever so slightly out on a limb without numbers to back me up, only history. People waiting for a bombshell that destroys Hillary, either Benghazi or the e-mail server, are very likely to be disappointed.
This presidential race looks something like an anaconda digesting a pig, long, ugly and inevitable. The more interesting contest will be in the Senate, where the Republicans have to defend 24 seats out of 34 being held. Predicting the House is much harder to do, though the Republicans losing the lower chamber currently looks unlikely. It all depends on how much of a drag Trump is on the ticket.