[4ePajero]

I found this web site, which has free download for routable maps for the whole world.
It might not be the most detailed maps, but for the occasional excursion to wherever, it will help you not to get totally lost!

Free routable maps for Garmin GPS devices

The Index of the tiles available:

The urban areas seem to be very well covered, the rural areas less so.

Examples of the quality (detail) of the maps:

Cape Town

Singapore

Sentosa

Bangkok