Well...Welcome to the world of CB..
It is indeed a nice and interesting hobby..
Plus given the areas you are likely to go in your dune buggy
(that is off the beaten path and or rural areas )..
having a CB for back up communications when you may not have cel service is priceless if you break down ( or worse )..
There are indeed many really good antennas out there..
However one of the plainest as well as oldest and most survivable antennas out there is indeed the 102 inch whip (yes get the spring as well) and a extremely hard to beat for transmitting performance as well..
Cobra CB's are fairly good..
Given you do not seem to be too concerned about money..
What about instead of getting a regular cb tuned up..
Why not look into getting something like an RCI-2970
it would offer 30 watts(more when properly tuned) on AM & 100 watts on SSB (again a bit more properly tuned) but would also offer many more channels (both above and below typical 40 channels of cb..