My friends and I have been extensively using S&T's to plan our 10 day road trip to Rushmore from Los Angeles, so I'll let you know how well it goes. I'll be bringing the laptop with me to help with any last minute changes or diversions should we find any :)
I'll be using a Holux GPSlim 236 bluetooth GPS receiver. I've used the receiver for nearly 2 years now (in Europe and the US) and it's proven to be very reliable and accurate.
I have it paired up using TomTom Go software, but I haven't tried it out with the laptop. I think a lot of problems people experience with the software is due to the GPS receiver not working properly.
In any densely covered area (big buildings like downtown centers etc..) GPS signal will be poor and will greatly effect the software's ability to find your location and navigate you correctly. For places like these, an external antenna is a must. I usually place mine on the roof of the car and string the wire along the weather stripping of the door into the cabin.
- Jonathan