A couple things to bear in mind. Legally, you're only to tow a certain amount of weight. Given you have a standard transmission, you're not allowed to pull as much as an automatic transmission equipped vehicle would. The specific weights are usually listed in an owners manual.
If you exceed this rating, you're faced with a potential problem. Say you get into an accident. Even if the trailer wasn't involved, or the accident wasnt your fault, your insurance company can (and likely will) toss their hands up and say "you're on your own", then leave you with the repair and towing costs. I'm sure there's other fees accosiated with that.
Now let's say you're pulled over for any given reason. If the officer finds your weight is out of compliance, the vehicle and trailer CANNOT move until the weight is brought back into regulation, which means you're stuck.
But, enough with laws. The Ranger is, usually, able to start a trailer with little issue. It may take some time depending on the given load, but it starts. However, the problem some face is actually stopping the load. I highly recommend trailer brakes for anything bigger than a 4x8.
Bear in mind Im no expert when it comes to trailers. I love the Ford Ranger, I really do, but in all honesty, it's not what you want for pulling regularly. The F150 or larger is better suited. That being said, that's not to mean the Ranger is incapable of preforming. My Ranger is capable of an 8,000 pound GCWR, legally.