My better half doesn't ride anymore either. I have these;
But have really only used one side bag consistently.
I have this for the luggage rack, but I'll bet it would fit on the back seat also;
Normally I just have one bag of my clothes in side saddle with rain gear, half bike cover, and extra shoes in the other side saddle. That leaves the trunk for miscellaneous stuff. I have a small cooler for the back seat and have strapped a tent on top for a long trip where we were camping occasionally. Last year I went with WARWGN on a 7,000 mile ride and I didn't have too much, or too little, stuff.