You can't save Fallout 2 from the munchkin thing. In Reno, you'll be able to fight 15-20 enemies at once, and as soon as you are in NCR, your enemies will wear CA (Darion's bodyguards), which means you simply can't just run there in a leather jacket. The main problem is only a "lack" of content in northern towns. However, as you said the problem mainly lies around New Reno. If it's not possible to edit rancom encounters there, I guess we can't do much about it... Removing good armors from northern traders might be a good start.
I heard modders like Brother Soifran were working on mods where you could be a farmer, so I guess we'll have to wait for that.