Making A Home For Stepkids

Given the decrease in time the stepkids spend with us anymore, I am not sure what to do to make our home seem like more than just a place they visit. It's always been their mother's intention that this be nothing more to them than the place they leave her for, not their home. She got her way after years of doing what she does best.

How do I make our home seem more "homey" to them other than adding a bunch of furniture that would stand empty and unused a majority of the year? The kids might be coming in April (my husband is going to request the time but it doesn't mean they'll be here) and I'd like to have or do something that makes it seem like home to them as well. They have our time when they are here, but it's not enough to make it "home". What can I do that would make a home they rarely come to seem more comfortable for them, like home?

Then I wonder if it is too late. At 13 and 16, have we lost them regardless of what we do...that's what I wonder.