Before you go out and buy a new truck, take the time to read up and find out what you need in a new truck. Nothing worse then spending big money for a new truck and still not have what you need to tow the trailer.
clickyThe payload number is going to be the biggest factor you need to consider. And you have to do a reality check to make sure you estimate that number adequately. 250 - 300 lbs ain't reality.
For myself, I had 800 lbs or more of stuff in my 25-foot trailer and over 1000 lbs in my 28-footer (or more depending on whether or not I was taking water with me and how long i was going for).