30Hart pretty well nailed it with his post. I'll add a few more info.
Hopefully you have lots of time and patience if you hunt either 38 or 1. As 30Hart mentioned the bulls dramatically move from where they are all summer after the first frost and when bulls shed velvet. It's really weird in the Bighorns but the moose are in the same willow patches all summer. Once the willows frosts, moose completely change their diets and moved locations in the Bighorns. I was warned this when I spoke to a local biologist and it was true on my hunt. Bulls also travel long distance once they shed their velvet checking out cows. It's almost like a switch is turned on and off how much they move. I'm sure once they find an estrous cow they will spend more time in that area but this didn't happen during the first 2 weeks of the archery season the year I drew.
Unfortunately on my hunt the light switch was turned off around a week prior to the archery season and bulls had already dramatically moved from where I found them every day during the summer. Some bulls were fairly close but boy it took a lot more work to find them. Most of the bulls.....and cows I saw all summer moved around 15 to 20 miles to the opposite end of the unit. Towards the end when I finally got my bull I had a tough time finding any moose. There was a 1' snowstorm that also made access extremely tough.
If you scout all summer the bulls may move 10 to 15 miles in 1 day once archery season starts. Also, if you find a particular bull during archery you better take advantage of it because he may be long gone the next day! I would definitely have bulls scouted before the season and hit early archery hard. I can guarantee things change dramatically as time passes into the archery season....and it may even be tougher finding bulls during rifle season. There is a lot of deep, dark timber in 1 and 38 but also lots of open parks and clear cut areas.
One nice thing about the early archery is that cows aren't in estrous so bulls are moving long distances searching cows. If you are at the right place at the right time bulls are fairly easy to call in. In fact, I called in 15 different bulls on my hunt. I hardly ever found bulls in the same location 1 day to the next...they were moving that much.
It's amazing how a lot of guys panic once they draw a tag. Many wait a lifetime for a Wyo shiras tag and shoot the first bull they see. There usually aren't that many top end bulls available and it takes a special bull to make B&C....if that's your criteria.
From my experience in unit 1 the genetics aren't the best for B&C due to how B&C scores moose. There are almost 0 bulls that make B&C with a spike on one side. There are a lot of spike browed bulls found in the Bighorns...some of which have nice spread, palm width, and palm length. I really wanted B&C on my hunt and passed up several literally huge bulls with spiked brows because I knew there were a couple whoppers with forked brows available that would make B&C. It was just a matter of having an incredible amount of time, work, and luck finding them once bulls started moving. I spent around 1 1/2 months scouting and hunting the year I drew.
There were a gob of archery elk hunters that showed up on my moose hunt. They can be both good and bad. They were more than willing to share info on where they saw bulls but it was pretty crowded at times.....possibly spooking moose.
In regard to horses, I really don't think you need them in 1 but they may help once you get one on the ground. There are some isolated areas in 1 with no roads but there also are a lot of roads scattered across the unit. I don't have as much experience in 38.
The moose are way more visible and easy to find during the summer in unit 1 than they were once archery season opened. This is just about opposite from moose found in other scattered units across Wyo. Scouting was a great time to see exactly what quality of bulls were available. With that said, I would certainly be willing to put in a lot of time both scouting and hunting if you want the best chance to harvest a monster bull. If size doesn't matter you can show up and hunt hard! Send me a PM if you have any other questions. I've only touched on a little bit of information I learned hunting shiras in the Bighorn Mtns.