there are at least 2 audio applications for Rider but I dont have experience of either.
Regarding maps, people cannot give you mapping as they are activated via ttcode.com on the Rider1 and the activation code will only work for one TomTom which will be the one they already have.
New mapping is automatically activated through TomTom HOME and the mapping is quite affordable.
Maps cost roughly £40 for country and £70 for continent. But unlike days of old this money pays for 4 maps distributed over 1 year and from the last map update you get a year of MapShare too, so in total you get 2 years of mapping updates for £40. Bargain if you ask me, especially when compared to other systems.