Advice for temporary living situation with cats

We currently live with two cats in a 3 BR/2B house with lots of room. They get along 99% of the time, but don't enjoy being in close contact at all. Next year we have to move and we'll be staying with a relative for maybe 6 months until we find a place. It's a 2 BR/1B and smaller than they're used to. They will probably have to share space more and be in closer contact. And they'll be making a 15hr drive to get there first, so super stressful start anyway.

Any advice on how to make the time easier on them? They've been together almost two years, so they're both kind of set in their ways. I know we all have to just get through it, but anything I can do to prepare would be appreciated.