Thanks. That's the sort of thing I was looking for, but I think it still has a way to go before it catches up with the stand alone GPS units (and puts them out of business). The reviews on Skobbler are very mixed, but reading them I found out about this one - OsmAnd. It gets mixed reviews too but a much higher ratio of 5 star reviews than does Skobbler.
https://play.google.com/store/apps/details?id=net.osmand&hl=en
By the way, what sort of holder are you using to prop up your tablet? It looks too far away though. I've got my GPS screwed onto the dash with a RAM mount. It projects forward a little so I can see it clearly. That could be more of a problem if using a bigger tablet as a GPS as I don't have that much spare real estate on my dash board that can be covered up by a big screen.