Tracfone Coverage Llano and Fredericksburg Area

[Outback]

I hunt near Enchanted Rock and want to be able to work during the day. My Blackberry tethers to provide internet service but I can't do a conference call and Webex simultaneously. I'm looking at pay-as-you-go phones with no monthly fees, just buying minutes. Anyone used Tracfones in that area? AT&T and Verizon work great. I will only use them 10 hours per year at most.

Thanks.