For whatever it's worth, Street Atlas 2010 Plus has the ability to transfer routes to a number of navigation devices. The list includes Garmin, Magellan, Lowrance and Brunton. Unfortunately I don't see TomTom on the list of devices.
If you are interested, make a quick route, click on the "Map Files" tab and you'll see "Route Files" and the name of the route you just created. Right-click on the name of the route file and select "Exchange". This will bring up the Exchange Wizard for exchanging data with a navigation device.
Click the "Select Device" button and select GPS.
Click the "Device Settings" and you can see a dropdown window with a list of devices.
Below those two buttons you will see a radio button to select "Send to Device". Below it is an "Object type" selector where you can choose to select either "Route Directions" or "Route Points". On the Device Settings screen you can enter the number of number of waypoints per route to allow.
Caveat: I have not tested this to see how/how well it works.
There is a conversion option available that you might be able to figure out how to get working.
GPS Visualizer: Web interface to GPSBabel
That's the online interface to GPSBabel. Or you can download the program.
When trying to convert data from one format to another, it's not very straightforward for some formats. For instance, it supports conversion from a number of DeLorme things. But it won't directly convert a DeLorme route by treating it as a route. You have to call it a Track to select a DeLorme format in the FROM file. But you can't convert a track file from any format into any of the TomTom formats supported. !!!
The only thing you could do to go from DeLorme to TomTom using GPSBabel would be to select the DeLorme Street Atlas Plus [W] ("W" standing for Waypoints) format for the input file and then select one of the TomTom POI [W] formats. Once the waypoints are loaded into the TomTom, of course, you would have to do the route all over again so that wouldn't be much help.
It's all a mess, and mainly because each of the navigation vendors wants to keep all their stuff proprietary so you are pretty much locked into them. Garmin's .GPX format seems to be the best supported when coming from or going to any other vendor formats, mainly because it's so well documented.
...ken...