in the 40 I could see you wanting the 2900. 75 w of power and 3w speaker so you can hear with all the road noise. Otherwise dual monitor is sweet to be able to monitor repeater and simplex. remote mouting is nice too. I have dual monitor in with the ftm-350 and want another because I want to be able to aprs, repeater and simplex. Now i know why guys have 2-3 antennas on the vehicle
the 1802 i have is nice and simple but even though it's fairly easy to switch freq it's a pita once you have a dual.
also get an HT and crossband repeat could be real useful for you in the backcountry martin.