[fidojoe]

Be careful when moving the tanks with the water in them, if you have too much water, they can fracture from uneven pressure. The other thing to think about is getting the new LR a week or 2 before doing the switch, and curing it in a 5 gallon bucket with a powerhead, that would be a better way than buying it, then putting the fish in right away, or a few days after.
Here's what I would do-
1. get new lr a week or so in advance, and cure it in a bucket
When its time to move-
2. siphon as much water out of existing tank as possible (into several buckets) putting lr into one (can be same as curing bucket) and fish into another.
3.move empty tanks to another room (existing will still have sand, and a little water)
4. Refill old tank with water from buckets
5. put fish back in, along with filtration
6. install new carpet
7. Set up new tank, add new sand
8. drain old tank (same way as step 2)
9. add old sand to new tank
10. add water, then lr
11. reaclimate fish

This is similar to yours, but not involving the new tank until later, to prevent it from cracking, and IMO, this migh be easier.