I installed the JT's on our Big Sky before we left WI. It took me about 2 hours for the four front ones and an hour and a half for the rear. On ours there was not a cross beam on the back to mount the rear units on so I had to add a 2x3 box channel just behind the telescoping jacks all the instructions come with the JT's. here is a slide show of installed jacks.
http://s212.photobucket.com/albums/c...t=48404260.pbw