As
@grsthegreat was alluding to, the weight of the trailer is one thing, how the weight is distributed makes all the difference.
In principle, a properly built and loaded 6,500lb trailer should have 10% on the hitch, I.e. 650lbs. If the the trailer is empty, it should be a piece of cake. Even if it is loaded, I think you will be ok if the load is centered at the axles.
TIP #1: make sure that you latch the hitch onto the ball, and use the safety chains. It gets to be so easy moving trailers with a PT that it is easy to get complacent.
TIP #2: Take your time until you get the hang of it, especially backing the trailer. Due to the articulation of the PT, it is like trying to back a double hay wagon, and trailer angles can get skew-whiff quickly.
If things do get sideways, don't forget, it is easy to drop the trailer, back the PT up to get a better angle, and start again.
I once turned a long gooseneck around in a tight T-intersection with the PT, and being able to quickly drop the trailer and pick it up from the opposite side made it a quick, little job.
All the best,
Peter