Yes, simple chain can be cut with bolt cutters, but a big hardened chain or cable can be cut with a cordless grinder almost as quickly.
Bottom line, make it "look" as secure as possible and don't leave it behind when you leave camp. For that, I'd get 2-2000s for easy portability.
When we camp with the camper on the truck, I'll typically chain the generator up to the camper or a tree/ picnic table etc.
if we dump the camper then I usually leave the gene chained up in the truck bed.
Keep your options flexible. One spot you may be good with leaving it in the truck, another you may want to secure it away from camp for noise purposes.