First of all, I would read the manual for your truck. It does address 4 down towing. I believe that a Ford Ranger 4wdr with manual tranny can be towed if you do certain things with the hubs, tranny and 4wd selector. However, I am not sure, so I recommend reading the manual. If you don't have a manual, you should be able to read one on line, or go to your Ford dealer and query a 4wd mechanic.
I have a '11 Ranger with manual tranny, 2wd drive and tow it successfully behind my MH. Love it.
Lee
2001 36' Kountry Star DP