I go alone most years, and I'm going alone again this year. Sometimes it can take a while to get the animal out. Last year it took me nearly 5 days to get my elk out because I had a really nasty gorge to negotiate and a 6 mile hike one way after that. But I had the meat in the creek during the day and I would hang it out at night. I kept it on ice at the truck. Everything turned out fine. I used to use a SPOT, and this year I am using the InReach. But many years I have gone it alone with neither. Like many have said, you just have to be conservative. Don't take big, or even moderate, risks.
The biggest challenge is the mental game. You have to force yourself to always stay positive. It is easy to stay positive when you are with a friend, no matter how tough it gets. But when you are alone there is nothing to gauge your mental attitude against. So, it becomes very easy to fall into a bad attitude. I have to always be keeping tabs on my attitude. It may be worth bringing along an mp3 player, book, or something to give you a positive influence. A Sat phone to talk with loved ones is a great idea. I really like the InReach because it has two way texting capability.
But the biggest thing is you just have to go for it! You will find much satisfaction in taking an elk and getting it out of the mountains alone. If you do harvest an elk and get it out alone, I would suggest you also process the animal yourself. If you do this I promise you will have a rare sense of accomplishment that only those who have done the same will understand. If you allow yourself to have this experience you will forever feel at home in the mountains.