Sounds like you are in for a good time, John! I'm jealous!
As far as working up to 56#, I did it exactly the WRONG way. I had shot a compound before, pulling low 60-something. So I bought a 60# @ 28" longbow, figuring I'd be pulling 55# no problem. Boy was I wrong. That's probably why it took me so long to work up to comfortably shooting that weight.
I did finally admit that I was way overbowed, and decided that instead of spending the money on a new bow, I'd work up to it. I tried to shoot everyday. Also, I'd string up the bow and put an arrow marked for draw length on it. Watching myself in a mirror, I'd draw it slightly longer than usual, and hold for 5 seconds. Did that three sets of 15 reps almost every day. My draw length "grew" from 24" to 26". So now I get the benefit of both higher bow weight and longer draw.
I was shooting a Martin Savanah, 55# @ 26", with 1918s or 1916s and a 125gr point, total arrow weight was ~475gn. I never managed to stick a deer with it, but I'm quite sure it would have been lethal if I put it in the right spot. Elk you'd probably want heavier. Personally, I'm a fan of aluminum arrows. Skinny, slick, straight (and restraightenable), consistent, not as light or expensive as carbon, not as heavy as cedar.
Good luck to you and your wife!