Yay, Toni! (Oh, I mean, yay, Dallas!)
I have a question about these wilderness races. Do they have people stationed along the way to give assistance to teams that get in trouble. Like, is there someone at the river to pull the mushers and the dogs out if they fall through? Or are you out there on your own most of the way?
LOL! I had nothing to do with Dallas' win!

He won in SPITE of my jinxing!
To answer your question - yes and no. There are officials in every checkpoint to help mushers in distress, problem is in an over 1000 mile trail you can't be whereever they are all the time as the racers are pretty spread out. In the case of the over flow in the river many mushers "fell through" but at different times. Normally in dangerous stretches of trail two teams will decide to run together/close enough that if one gets in trouble someone else is there.
Once someone outside of the race helps you, you are disqualifed (other racers can help, but if an official trucks you to a checkpoint back or forward you're done). This is about you and the dogs type thing.
Officials are constantly watching those areas that are trouble spots, though, and are watching each musher's GPS tracker. If a musher does not check in to a check point within a given timeframe - as in teh case of Hugh Neff during this race - then snow machiners are sent out to find out what is going on. If a musher is just hunkered down due to sled problems, they're resting, or the dogs have decided they aren't moving just yet, then the snow machines head back to the check point and report everything is fine. Airplanes and other mushers info is also used to deal with these issues.
Dallas was helped out of the river by, I believe, third place finisher Ken Anderson. Hans Gatt (who ended up scratching because he was teh first to fall through and was stuck in the water for quite a while - he rescued the dogs and they were fine, but he went back in for his sled and ended up getting stuck himself) was helped by second place finisher Sebastian Schnuelle.
in 200... I want to say 8... the Iditarod saw new rules come out of a stupid rookie deciding he could take his team out into a blizzard. (He should have stayed hunkered down on the trail, but he decided to plug on. He got stuck, nearly died and a lot of his dogs did get sick or die... it was absolutely STUPID what he did, and he got heavily chastised for it (after he recovered) by the mushing community even though he, too, was upset over his loss. But he claimed sleep depravation. So new rules were set in place on rookie mushers, and many more miles/races have to be under their belt AND a veteran of the Iditarod must sign off on the rookie before they can apply to be part of the race.
These races are about the dogs at all times. In fact the volunteer vets are an amazing team of people who come together after every race to discuss how to make it even better for the dogs while still being a challenge. The Iditarod celebrated the biggest vet achievement last year as there were no dog deaths in the race. A first. I know that makes the race sound cruel, but these dogs not only love what they do (I've seen the dogs that have to stay home, they're the ones that look abused lol they look so rejected) and those that do die would have the same sickness/issues as they would if they were just regular outdoor dogs. More dogs die on percentage as "house pets" in the same two weeks than do the Iditarod or Quest. They're taken better care of vet wise and owner wise than most couch potato dogs. My dog was severely over weight until I started working with Dallas and his family and realizing how to regulate what goes into my dog's body. My vet saw the improvement right away and LOVED it.
There's no reason for the mushers to abuse their teams, it will discourage a champion team. Dogs won't run if they aren't happy. Just ask Ramy Brooks' team where he got frustrated with his dogs and began smacking them to try and get them to run. The dogs laid down and wouldn't move. Unhappy dogs do not run and win the Iditarod... they just don't run period.