A few comments because I always have a few comments.
I believe if you don't ever want to boondock, drive on the beach, climb a dirt road or drive in snow then a 2wd will be just fine. If you do the math, it would probably be cheaper to pay a tow now and then than to pay for 4wd. You can get towing insurance with your car insurance for only a few bucks and that would cover it all.
Sometimes 2wd has a higher towing and hauling capacity but not always. You have to look at the specs to be sure. Sometimes 4wd has a higher rating.
Often the mpg of a 2wd is higher than a 4wd but not always. BMW did some testing and determined that there are times when AWD is more economical than 2wd. It has to do with the rolling resistance of
tires. An idling tire has a little more rolling resistance than one that is pulling a little. That isn't likely to be the situation with towing but it isn't clear cut.
If you are choosing between a long bed and 4wd then your budget is pretty tight. You could find a very low miles used truck with both and save even more. You could even get a higher trim level truck for less.
2wd trucks are generally lower to the ground than 4wd trucks making them easier to get in and generally easier to deal with.
2wd trucks are typically cheaper to maintain/own.
Most rwd cars have close to a 50/50
weight distribution. Fwd cars tend to be more like 70/30 with more
weight on the drive
axle. Trucks are normally
light in the rear. That means trucks are least capable when traction is low. This is offset when towing to a large degree because of the tongue weight of the trailer.
In my mind, and only in my mind, SUVs are cars that want to be trucks. Compact trucks are cars with big trunks. 1/2 ton truck are borderline but useful. Real trucks start with 3/4 ton and go up from there. That doesn't mean you can't tow with smaller vehicles though. I'd have no problem towing with a Subaru Brat if the trailer was small enough. You don't need a 4wd 3/4 ton diesel truck to tow an FGRV.
With proper prep and good skills you can take a 2wd a lot of places that people get stuck in their 4wds. Such prep and skills typically come from sad experience though. Simply by keeping up a bit of momentum you can get through a lot of things that seem iffy.
I drove a Mazda Protege (small fwd) from Boise to Portland one winter. When I got to Baker City the freeway was closed. I took the old highway until I got to Haines, Oregon. There the old highway was blocked off. I took city streets to get around the barricades, sliding through 2 prospective turns before I got back to the highway. I then proceed westward on the highway. I watched a Toyota pickup in my rear view mirror with oversized off road
tires do a pirouette and run off the road backwards. About 5 miles down the road I waited while a convoy of 2 trucks and a Suburban entered the highway. I followed them into LeGrande. They broke through the 4-5 drifts across the highway and I hit the drifts at about 20 mph to not get stuck. I never slipped, slid or spun between Haines and LeGrande.
Someone who doesn't know what they are doing can get stuck in a small puddle. Someone with a little experience can go a lot of supposedly impassable places just fine.
Diesel engines are nice for towing because their power peak comes lower in the rev range where most towing happens but unless you tow a lot they will never pay for themselves.
All of the above not withstanding, I don't think I will ever own a 2wd pickup. It just doesn't fit what I do or hope to do with a truck. Again, in my mind only, real pickups are 4wd, and I'm not alone. Where I live in Idaho there are probably ten 4wds for every 2wd. Of course we have snow. Interestingly it tends to be farmers that have 2wds but then they also have a 4wd.
Around here 4wd sells used for about 2-3 times the price of 2wd and diesel adds another 50%.
I was contemplating getting a 2wd for towing since I already have a 4wd. My wife nixed that idea right off.