you could try putting the regular mattress on the floor first(just a thought) - that is how we transitioned, but did not have a house move to deal with

New house, new bed might be too much "new"... I guess part of it depends on how attached he is to his bed? Having the same bed might be good for his sense of security...? At least for a bit.

I think mattress on the floor is a great transitional move. Start with his toddler mattress, get a bigger one a bit later, then move it up onto a frame. Good luck!

My kids actually took to our move pretty well. There was a bit of a weird time, a bit of acting out maybe an extra meltdown or two for about a month but it wasn't nearly as bad as I was dreading.
I would just talk to him a lot about cool his new room is going to be and try to get him excited about his big boy bed. You'll do great!