Also have in mind that zumos use lithium-ion batteries that when off the power would work for 2-3 hours tops with screen on. The 60csx for example uses 2xAA and lasts 20+hours so you can also take it with you. For my setup I use a RAM mount, a bit expensive but very strong and modular, 12V power socket, 12v-to-usb convertor, and mini usb cable. That way when it rains I just take the cable off and can go on for a long time without external power and can take the gps with me if needed. The 60csx is a bit slow in a city with lots of data on the map but on the road it's just fine. It also uses old fashioned buttons and not touch screen so for me it's much easier to operate with gloves on.