RE: if you have to let one go overnight before tracking...
About 10 years ago, my buddy and I each shot a buck about 1 minute apart. I thought I heard mine crash about 60 yards behind my stand, but we saw his fall and went to retrieve it first. This was at about 6pm on sept 21st and the temps were in the mid 70's.
It took us until after 11pm to get his back to my truck and I was working OT the next day and couldn't look for mine until after work the next day . . . at 4pm. It had rained HARD all night and no sign was found at all, but the buck was lying right where I'd heard it crash . . . and it stunk pretty bad.
I gutted in anyway and took it to the butcher near by for a professional opinion. With all the stomach contents removed, it looked and smelled fine to her. I iced it down immediately - her advice - and took it home where I butchered it. It was possibly the best venison we've ever had and we all lived through it with no ill effects. That's nearly 24 hours in temps in the 70's and it was fine.