Four down is easier. Two pins, two safety cables, power cables for lights, car in neutral and maybe pull a fuse and you're ready to go. That's me about 3 minutes to connect or disconnect. The down side is you'll need a car that has a transmission that allows plus a mounting bracket installed on that car. Total cost can add up quickly for a tow bar, brackets (aka base plate), may be a braking system, lighting circuits and such. Throw in the cost of buying a vehicle just for the purpose, $$$$$.
Dolly towing is a bit less expensive and just about any conventional front wheel drive car can be towed. Down side is messing with the dolly at home and at the camp site. A hitch on the toad will help to move the dolly around. Getting the car on the dolly is a bit more work and you'll need to watch the tie down straps. You could have your state of residence plating requirements, inspection and yearly tax with a dolly also.
I tow four down only because I already had a compatible car in the drive way when I started. I probably would have gone with a dolly rather than buying something at that time just so I could tow four down. If my one car that is configured for towing breaks down of is no longer usable I'll need to spend a few $$$ to get the second vehicle we having in the driveway ready for four down towing. If I had a dolly no such cost.