All you can do is add a waypoint to your house. Then it'll know where you are. You cannot really add a road or path to your house. The GPS will autoroute to your house using the waypoint. Then for the last little bit you'll be on your own.``
And you can customise that waypoint icon to show a likkle piccy of a house too.....then go to options and set that W/P as 'home', then when you press and hold 'find' for a second, it'll route you there in one button push from wherever.
As Richie says though, you can't actually add the road.
I was always taught that there is no such thing as a stupid question, merely people who are too stupid to ask questions when something crops up that they don't understand.
With the free version of GPSmapper if you modify your current City Select/City Navigator maps and save them then you will lose the auto-routing data and POI
With the paid version you will still lose the auto-routing data but will retain the POI (I believe).