You can pan in and out. The more you pan out the less detail it shows.
What I would do is if you know the area in CO that your giong to hunt I would get familiar with they area on my computer in Topo. The only downside to the GPS unit is that you are looking at a small screen as when you pan out the screen can't fit all the info in for a huge area. I would also suggest if you are that unfamiliar with the area then have a topo map and compass and use them together. It would be a good safety feature if you broke your unit. Map and compass are under $10 and good insurance.