I have had a lot of offroad vehicals over the years and this is my personal take on them.
Rail Buggies, PROs Go like hell super fun to drive very comfortable ride will almost go anywhere Lotsa places a truck can't go easy to work on.
CONs getting harder to find parts for and price is going up, limited storage spaces, no weather protection, don't go well in deep mud.
Small trucks Pros- toyotas are damn near bullit proof, go almost anywhere, better storage than a buggie, closed cab for foul weather, lotsa parts and can be made into a diesel easy, don't attract much attention. decent fuel mileage.
Cons- Ride like a jolt wagon, kinda pricey unless your a scrounger, not much power unless you modify them(not always a bad thing)
Full size or SUV- Pros- Plenty of storage more so in the cab plenty of power, can be had very cheap. easy to find most parts, can be used as a shelter also, diesels are abundant.
Cons- To big to get back into some of the ruff country I am going into, no fuel mileage, newer one are way to complicated older one are wearing out, More prone to breaking on trails because of size and power.( there two best assets)
My choice is gonna be the Toy because of the size mostly they will fit places a fullsize won't and will carry all I 'll need them to, getting rid of the gas motor should increase mileage and low end power and fuel should be easier to come by which is what I feel I'll need where I plan on running to if that time comes. Just MHO.