Hi Ric
The suggestions you received concerning shortened dipoles are a good place to start.  A picture is a thousand words and if you can have someone who has some experience look over the property and tell you realistically what you have room for that might be a start.  I too have power line issues here.  I would love them to be underground but that's not to be.
Are you currently using some type of cushcraft antenna for hf?  If so, I'm curious as to what you are using?  Summer can sometimes be slow on the bands so don't be discouraged.
Richard