do you have an extra set of hands?
the hardest part of it is putting the tank back up. get it on a jack, push it up and make sure all lines are clear. if its positioned properly you can just put both straps on and its pretty simple. i would say 30 minutes up to maybe 2 hours depending on how smooth it goes.
as stated, make sure you have as little amount of fuel as possible for REMOVAL AND INSTALL. unless you like pools of gas. just MAKE SURE you have sufficient amount of gas in the tank for first prime or you might as well take the pump right back out and put in another.
i had one prime dry briefly, lasted 7 miles. then somehow when we put my same pump back in i ran out of gas and it lasted 40 miles after that.