My main route vehicle is a 2002 Dodge Durango. It had 60,000 miles on it when I purchased it four years ago, now has 191,000. It's a beast in the snow. My current backup vehicle is a 2006 GMC Canyon. Both of my vehicles have towing package and off-road package, so they have additional transmission cooler and heavy-duty suspension. My first route vehicle was a 2004 Chevy Venture, great route vehicle 20+ mpg on the route, tons of room for parcels but only front wheel drive and the gravel roads eat up mini-van tires.
Other carriers in our office (all POV on the rural side) use: Honda CRV, Chevy Blazer, Chevy Impala (bench seat), Ford Taurus (bench seat), Ford Escape, and a Kia sedan of some sort. A couple of the regular carriers have RHD Jeep Wranglers. One of our RMPO subs had a dual control installed in his route vehicle, but I don't know what type of vehicle he has.
My suggestion is to use what you have or what you can get really cheap at first. Look for removable console, shifter on steering column, or even bench seat. Think of your height and arm length versus the vehicle. A taller person might be able to use a full-size 4x4 truck. A shorter person (like me) couldn't reach across a full-size truck. This job isn't for everyone, and the hours are usually famine or feast. Make sure you like the job and can handle it before investing a lot of money in a route vehicle.