Well awesome. I would encourage you to price taking slash to your local dump ASAP so you know what you are signing up for next time the phone rings.
My wife wants a AWD Rav4 for her next car. Late model inline 4 cylinder motor toyota listed max is about 1500# for trailer and cargo, if you have a V6 total is 3500#. About. Check you manual. Can your SUV take a hitch receiver?
I don't know every small truck out there, but in general Ranger/Tacoma sized trucks are listed for 800-1000# of cargo just in the bed. Again, check the owners manual, but if you fill the thing up in the AM and split it all at home and get it stacked in the PM you have put in a good hard day. My 1999 Ranger had a class II hitch receiver bolted to the frame, pretty common in my neck of the woods. Trailer balls bolted directly to the rear bumper are hardly ever class II, check the manual on those.
My 2015 Tacoma has a class 4 hitch on it (12,000 pounds). If I had special ordered my Tacoma I would have specd a class II hitch, but I got the 4. Class IV realistically requires a trailer brake controller in the cab and some kind of braking system, usually electric, on the trailer. I am new at this class IV trailer stuff, but nice class IV trailers have dual axles and cost $5k for a cheap one. Hitches are downward compatible, if you buy a truck with a class IV hitch you can hook up a class II trailer and follow the class II guidelines without having to do all the class IV stuff.
I know from experience you can wear yourself out easy scrounging wood with a Ranger sized truck, no trailer, and a 40 hour per week regular job.
If I had to pick for scrounging, between a 4x4 truck that could take a receiver someday and a class II ball someday and a class II trailer someday, or a two wheel drive truck with a rcvr and a ball and a class II trailer today, both for the same money, I would take the 4x4 every time. You got an awesome neighbor, and you want to keep him happy just for the reference, but there is more.
The real hook up is going to be a builder. When a builder buys acreage, he wants it cleared yesterday. If you can show up every day at 11AM and cut for a couple hours and load up your truck and drive away, and come back on the weekend with a trailer and cut even more you are going to be invited back and he will tell his builder friends.
That kind of rep will snowball, even if two cords a week is all you can pull. If you are dependable and show up when you say you are going to show up, it doesn't matter if you show up with a 1999 Ranger and a $600 trailer from Tractor supply, you will get called before the guy with the 2015 F-350 and the $20k trailer who shows up three days late. If you are helping builders clear lots you are going need four wheel drive, the roads are where you put them ;-)
In my area builders often "invite" three or four people to come take the trees, its kinda first come first served; remember the builder wants it gone and doesn't care who takes it. Generally the other invitees are just as cool as you are, you take what you can cut, they take what they can cut, everybody wins. If you know all the cutters it might be OK to buck and buck and buck during the week and come back with a trailer on Saturday. But if you buck and load everyday you don't have to worry about strangers loading up the rounds you bucked while you aren't there watching.
I would advise you to keep your neighbor happy, ask him to tell his friends. Also, small sticks of cherry, no matter how bad they are, burn cheaper than propane. I'd go down to about 1" diameter myself, but I burn about 8 cords per year.