I can't give you any concrete product suggestions. There are so many variables.
I've been a GPS receiver owner since early 1995, and I have used them on my job, so I take performance seriously, and I taught classes on it for years. I've used one or the other on five continents, and one sort of saved my a$$ one time. I've owned only Magellan and Garmin products, but their are some other brands.
The simplest GPS receivers have very simple features. They show you a bunch of numbers in latitude/longitude (or similar scales), and you have to look that up on a paper map. You can mark your position, like the position of your Jeep, and from miles away, the GPS receiver can point you back to your Jeep in terms of distance and direction.
The next family of GPS receivers has all of the simple features, and then they have a map database built in. In some cases, that might mean topographic maps, and in other cases it might mean streets and roads. Some GPS receivers can be switched from one map database to another, like topographic in the woods, and streets when you are in town. In some cases, the map database is built-in from the factory, and in other cases the user has to add maps from a computer-based DVD.
When you think you have some brand and model picked out, you might want to go to some electronics retail store and see if they have a demo unit that you can hold in your hand. The reason is that some have a large display, and anybody can read it. Others have a small display, and they might not be good for some people. You almost have to see it to understand if it is right for you.
–B.G.–