FYI, you can weigh your tongue w/a fish scale. (wish I were photoshop proficient for that one!)
I notice trailer most going in/out driveways with a dip, if the trailer wheels go over it separately you feel a little head shake but your going slow so it is no way upsetting.
another thing to consider, safety chain? if so will the trailer bring you down into the ditch or into oncoming if it has a flat or other failure?
If you don't safety chain will you be cited by law enforcement? could it break away and kill someone other than you?