I need to show three long routes - about 600 points total - on a map of Canada & USA.

This is a one-off project and I'll then print out the result & hang it on the wall.

Will do this on a Windows PC & I can generate the points in Lat/Long.
(At the moment they are a mixture of Google Maps street addresses & Lat/Long.)

I've not been able to make Google Maps do a route of more than 15 points (even using the API).

Some control over the 'density' of the map's detail (political boundaries, cities, rivers, highways, etc) would be nice.

Anyone have advice - or where to look for it ?