I wrestled with spare tire a couple of times, and even considered getting an extension, but found an easier and more convienent way to hitch up.
I regularly pull a cargo trailer with my 2005 CRD with factory receiver. Rather than use a hitch extension, I just attach the ball and hitch to the trailer coupler then slide the hitch into the reciever. Its fairly easy to do since I have a tonge jack with a small tire on the end.
When I drop off the trailer, I just pull the pin and drive off. Very easy.
Its a little more difficult with my boat, only because the trailer is much heavier, but still do-able.
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2005 CRD "
Ol' Blue"
Red Ryder carbine-action, two hundred shot range model air rifle with a compass in the stock and this thing which tells time.
My build page- RL Komodo Rear and TJM Front Bumper, armored, lifted, JBA Steel D30, 4.10s and ARB air lockers.