Afton Hills Ultra?

If Afton Hills is in Minnesota then hot and humid is highly likely. Unless it rains to keep things cool. Worst scenario is it rains then the sun comes out, super humid. I've never done any races at Afton so I can't help with that. I used to live in Minnesota for 30 years.

As for aid stations the race website usually gives a break down on distance. I've done ultras where they are 5 miles apart. Just finished a 50k that had them 8 miles apart due to being remote.

I did the 25k there last year and am signed up for the 50k this year. That is, if you're talking about the Afton 25/50k in MN.

The course is a little hilly, but nothing brutal and none of the hills seem to go on forever. They're steep but short. There's long sections of decent runnable terrain as well. The portions out in the open prairie/grasslands will be hot and humid, but they're mostly flat so it's not too bad to at least shuffle along at a slow, yet still running, pace. The 50k is two laps on the 25k course.

It's a good race despite the fact that it's July in MN and will be hot.