I'm fairly new to 5th wheel towing and it's definitely easier backing a bumper pull than a 5th wheel but I'm getting better with practice. "Following" the trailer sooner is real important for effective backing. I also don't hesitate to frequently pull forward a few feet to straighten out the relationship of truck to trailer. Where I store it I'm forced to back in on my blind side without a spotter. I simply get out of my truck a couple of times to see where I am.
My advise is to take your time and have a spotter on your blind side.