Do you need to talk or will passing messages (data) work for your needs?
How wide an area will you be mobile? That is to say - just around town or cross county (Denver to KC for example.)
Meteor burst is an option, but will require some rather specialized accessroy equipment for your mobile rig.More here
he United States Department of Agriculture (USDA) uses meteor scatter extensively in its SNOTEL system. Over 800 snow water content gauging stations in the Western United States are equipped with radio transmitters that rely upon meteor scatter communications to send measurements to a data center. The snow depth data collected by this system can be viewed on the Internet..
Meteor burst communications faded from interest with the increasing use of satellite communications systems starting in the late 1960s. However, in the late 1970s it became clear that the satellites were not as universally useful as originally thought, notably at high latitudes or where signal security was an issue. For these reasons, the U.S. Air Force installed the Alaska Air Command MBC system in the 1970s, although it is not publicly known whether this system is still operational. (THe USAF MB system was pulled from service in the late 80s - removed in the 90s.
In Alaska, a similar system is used in the Alaskan Meteor Burst Communications System (AMBCS), collecting data for the National Weather Service from automated weather stations, as well as occasional data from other US government agencies.
Most meteor scatter communications is conducted between radio stations that are engaged in a precise schedule of transmission and reception periods. Because the presence of a meteor trail at a suitable location between two stations cannot be predicted, stations attempting meteor scatter communications must transmit the same information repeatedly until an acknowledgement of reception from the other station is received. Established protocols are employed to regulate the progress of information flow between stations. While a single meteor may create an ion trail that supports several steps of the communications protocol, often a complete exchange of information requires several meteors and a long period of time to complete.
Any form of communications mode can be used for meteor scatter communications. Single sideband audio transmission has been popular among amateur radio operators in North America attempting to establish contact with other stations during meteor showers without planning a schedule in advance with the other station. The use of Morse code has been more popular in Europe, where amateur radio operators used modified tape recorders, and later computer programs, to send messages at transmission speeds as high as 800 words per minute. Stations receiving these bursts of information record the signal and play it back at a slower speed to copy the content of the transmission. Since 2000, several digital modes implemented by computer programs have replaced voice and Morse code communications in popularity. The most popular program for amateur radio operations is WSJT, which was written explicitly for meteor scatter communications. Note that data rates are on par with packet radio - that is to say, slow.
Sources for software - http://physics.princeton.edu/pulsar/K1JT/http://www.aprs.org/meteors.html
(6M MB activity)http://www.dxzone.com/catalog/Software/Multimode/
For years the USGS tracked choppers in the bush via MB communications, along the lines of APRS, and I worked with the Alaska meteor burst system for a number of years. It does offer a means to communicate over a wide area on 6M or even 10M. Power levels of 45 to 60 watts are the norm.
Hope this is of use.