We started a few years ago taking a trip for our anniversary, plus the overnight trips to my parents house and a couple other overnight get aways over the years led me to make sort of a "bob" that doesn't look like a bob on the outside.

What I did was take a couple of those big ziplock baggies and put in our suitcase then started buying small items we would use when overnight so we had less to pack before a trip. Those grew into mini bob's so if we ever did need to bug out we can grab the suitcase and go as it has a lot of the things we need for a non-wilderness environment, for example say we had to evac like the residents of NOLA a couple years ago and stay in hotels or other peoples houses the contects of the suitcase are sufficient for that.
Then we spend time in parks and/or camping so I put together a backpack with everything we might need/want/use for those outdor trips and it goes with us on them. It grew into my bob so that if we ever did bug out I have everything we need there as well.
None of this appears to be "survival" related so it doesn't take any convincing, its just stuff to make our normal trips easier.
Suprise your wife with a weekend get away to a cabin or bed and breakfast then afterward tell her she should have a travel bag ready at all times in case you ever wanted to do that again. I haven't done the surprise trip yet but those trips we do take are tests of my bobs to see if we need anything else or how long it takes to get ready to go.