Hi THP1156,
In addition to all of the things you mentioned, you could give the dispatcher access to a computer with internet connection to Google Maps and just give them your coordinates and they will know precisely where you are, regardless of the existance of cross streets/roads or mile markers.
With a cellular aircard plugged into your laptop there are also inexpensive solutions that would allow the dispatcher to track you in realtime, or near realtime, any time it was useful. But that's probably going a little farther than you want to at this time. Maybe next year, eh?
Now, back here on Planet Earth, there are some cautions you should be aware of. Even with Navteq's data, the data is almost never more current than two to five years old. The farther away from a large urban centre you are, the more likely it is that data will be out of date or missing entirely. For the most part that won't be an issue because you will most likely be dealing with locations like major intersections and other sorts of things that have been around for long enough that they'll be on the map.
Where you will encounter problems will be in newer subdivisions or anywhere there have been major changes in roads and streets in the past few years. Another place you may encounter problems will be outside the city, on side roads and gravel roads. In some cases you have to zoom in quite tightly for them to show up. In other cases they simply won't be there at all (this mostly applies to sparsely populated rural areas).
Before committing, you need to take a look at the map data for your area to see what it shows you and see if it has enough of what you need to solve your problem. You can get a look at the latest Garmin North America product on their online map viewer. The data is supplied by Navteq so you can be confident that if you see what you want in the online viewer at Garmin, it will be there in any other product that uses Navteq's data of that same vintage.
To use the map viewer,
go to this page. About a third of the way down the page there is a grey legend that says "MapSource Map Viewer" and just below it is a dropdown box that says "Select a map product". Click the dropdown box and select "City Navigator North America NT 2009". That's the mapset that comes with Mobile PC. It's a little slow navigating around in the online viewer and the display is a little crude compared to how the maps will display in Mobile PC. Well, it's really crude compared to how beautifully Mobile PC displays the same data. But it's free and will let you see what you need in order to decide whether the map data contains what you require.
You can select more or less detail. If the detail you want to see doesn't show up, keep zooming until you can't zoom in any more. Certain details do not show up until you are zoomed in to a certain level. I like to click for the Large version of the display and click for More detail. That slows things down and can make the map really cluttered in certain situations, but it's easy to click for less detail or simply zoom out a bit.
I hope that's helpful.
...ken...