I googled "AC595U router" and the second result was this
http://www.topglobalusa.com/product2...ssid=102103102 it is a router that supports usb and pcmia wireless modems without the need for drivers it has wireless and 4 wired ethernet ports on it as well. My suggestion for you is to get this router and then get a usb extension cord long enough to mount the data card in a spot on your truck by the back window or hogh up on the front window so that it will recieve a good signal. If the usb data card has ports for an external antenna just get a good 5-8dbi antenna and mount to it leaving the shortest cable you can from the card to the base of the antenna the longer the pigtail the more signal loss thru the cable so a 10ft pigtail cable would probally loose all of the signal that it gains. The only pics i have seen for it does show a ruber plug on the side that would indicate that it does have a port for an external antenna.
upon looking up the specs i came across this.
USB Port Connectivity form factor is designed for multiple computing devices that are equipped with a Type A USB port, including devices that do not have PCMCIA card slots
2–Way Text Messaging Support (via VZAccess Manager)
Email Access
Removable Battery for Power Boost
Docking Cradle for Fixed Solution
External Antenna Connector
Meets FCC SAR limit. Manufacturer's highest FCC reported SAR 1.240 W/kg. Actual SAR may vary.
Then i found this searching google for 40 bux + shipping.
http://www.antennagear.net/servlet/t...95U-USB/Detail
11dB Sierra Wireless AirCard 595U USB Modem External Antenna
I don't know what your budget for your setup is but to complete what you want for total mobility you can add to the usb hard drive to the router wired to one of the ethernet ports with a Linksys Network Storage Link NSLU2 NAS server
I have not seen great reviews on the device performance wise but for your setup i don't think you will need that much bandwith and it would complete what you want being able to mount the hard drive to the router having the usb data card plugged into it sharing the cards internet over the routers wifi. For the router and the adapter they run off dc normally 5-12v @ 500 to 1000mah so im sure you could get a dc power supply to just be able to use the trucks dc without the need to get an inverter for the included adapters to transfer back into dc again kinda pointless unless its cheaper for u to get and hard wire an inverter up where you plan on hiding all this equipment.
Sorry for the long post but this will end your searching and maybe free you up from having to have a pc always on connected to the net @ your house just to acess the hdd in your truck from the phone. and or having to hook up a pc/laptop in the truck to share the internet connection off of the card. In the long run if you got these parts it would save you money from not having a pc @ home churning away @ the electricity.