Yeah the wife is a great asset. Once I showed her the spot that the tires get to so she can let me know when to turn after a few stops she just gets it. Her primary job is keeping an eye on the side that I can't see after that.
Biggest trick is not to over steer the turn and prep your turn by positioning yourself properly.
The fifth takes longer to start that turn but essentially is the same trick as any tow able. Don't over steer. Once the unit starts it's turn it will keep turning until you apply pressure on the opposite angle to cancel the force. No reason to over steer, just get the truck centered after the turn starts and use small adjustments. That is the biggest error I see most people make when backing in.
Starting out in a good position is also paramount to an easy turn in a tight area. Getting the unit on a good angle so you aren't trying to turn 260 degrees is paramount to easy backing. The larger your angle over 180 degrees (straight back in) the harder your turn must be and the harder it is to get the timing on getting the truck straight.
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The closer you start that turn to 180 degrees the better so pull up to the site close on the passenger side, ride forward until the rig is coming across the driveway and your goal is then pull forward and out hard driver side so ultimately the passenger wheels come up on the edge of the patio side of pavement and just a tad beyond as you straighten out the truck and trailer so you are able to start backing. Obviously opposite if you're backing from the other direction.
So long as the rear of your unit can swing without smacking trees the only thing you need to worry about is the back tire location as that is the path the unit is going to take. Adjust that from there to account for foliage but the pivot point is going to be the back axle and the back wheel is where the turn will start once the units begins turning. The giant box hanging off the back is irrelevant except for obstructions. which you should have 15 ft+ of drive way width to use.
Start your turn backwards and once it starts turning good get the truck straight. Keeping the unit moving the direction you want. Once you get that point down it is like butter.