You can get a fan switch the turns on 10-15 degrees after the thermostat opens and turns off right around when the thermostat would start closing again. So, if you have the factory thermo, they can open somewhere between 192-197, get a switch that turns on around 200-205. That way it will regulate and won't stay on all the time or run too hot. For the most part it will run while you sit in traffic. It will cool enough on it's own while you are driving. Also, get one that has the a/c option. That will turn it on anytime the a/c compressor is engaged or it won't cool. Find a 16" fan that is at least 2000 cfm and higher. The higher the better, it'll cool better. Zirgo makes some decent fans for the price/cfm rating. 3000 cfm for around $100.
1995 XLT 4x4 Supercharged 4.0. Lot's of stuff. Check profile.