Thank you all for your feedback. My wife and I parked our trailer with just walkie-talkies. It was a pain, so I am looking for possible options. In addition; due to clearance I need to replace a 2 part gate to a single one mounted on the fence post able to swing uphill which is another cost of a most likely custom gate, I had to remove the gate to get the trailer in. The following options with some variations are left for my final decision:
1. Push with my truck and mount a camera
Rear View Camera on the rear trailer's bumper which would be connected to my currently installed rearview system. I still have one available channel on current installation. Align the camera with the concrete expansion joint. Adding a quick trailer connector would speed-up set-ups.
2. Push with my truck and mount wireless SenseStat sensors on the trailer
SenseStat Obstacle Detection Sensor System Wireless - $254.09
Due to 80 degree sensor ultrasonic cone shaped beam and minimum working distance of about 6, sensors would have to be mounted about 20 above the ground, 18 in from the trailer sidewall and 7 behind the rear bumper.
3. Utilizing the driveway slope, use a custom 4x4 trailer dolly with an offset shaft allowing me to see side clearance during controlling trailer direction while winching. Use a winch mounted on either dolly or the truck to let the trailer go down and up.
I am leaning towards SenseStat due to accuracy.
One of the options I evaluated was to use a very expensive EU style trailer movers permanently attached to the trailer capable of moving single or dual
axle trailers
Compare Caravan Movers. They would fit perfectly my application of 2-3% slope. These movers are popular in the EU, but the only company which distributed one of them in the US is out of business -
Powrtouch Trailer Mover so I asked myself why. The trailer movers which are popular in US are under trailer tongue movers. I think that the reason is that
weight of hitches in the US is much higher than in the EU increasing the turning moment in consequence overwhelming the movers. So, I dropped that expensive option early in the process.
George.