A black steel fence, in the overall landscape picture, is relatively transparent, so I wouldn't use that with the intention of trying to stop a view, per se. More effective, I think, would be a white picket fence. You need it, also, to create a limit to the neighbor using your yard in any way. If the pickets were fairly close together, when viewed at an angle, it is enough to create a visible and physical divider. The rest of the effort needs to be in shaping the view toward the entrance of your own house front so that the neighbor's yard and his belongings become part of an indistinct and vague background. Once your tree becomes tall enough to put his vehicles into some shade, they will be less noticeable. Shrubs or tall groundcover in front of the fence will obscure the view beyond even more. A large shrub at the corner of your house would do a lot for obscuring the neighbor from anyone who is entering or leaving your house. Doll up the rest of your own landscaping so that people want to see that view. You could start by widening the walk some and creating a landing off of your stoop, so that it seems more inviting. Also, Don't obscure/pinch the steps with plantings or planters. Add color flanking the steps with annuals in the ground or place the planters toward the outside edges/corners of the stoop. If the steps are not wide, widen them.

I think it is a mistake trying to hide things by using low hanging branches of trees when there is a simultaneous need to see the view of your own things beyond (house, for instance) and have the space look like it is properly maintained. Low hanging branches make a place look neglected. They are not made to comfortably clear the head height of upright walking beings . It is much easier to hide things that are between 0' to 8' tall with shrub form plants the screen from the ground up. Use tree foliage to hide things that are above that height.