We only make reservations when we want to be certain we will have a spot where we are headed. If we are in route then we wing it. When the DW and I rode MC's we just hit the road and where we ended for the day we looked for a hotel. Wife hated that. I loved it cause I wasn't tied to a schedule. When we started RV camping, the places to stay dropped drastically. There are way more rooms at hotels than there are spots at CGs.
OP, I can understand your DH's reason for not wanting to be regimented. Sometimes trips don't always go as planned for the good or bad. Staying an extra day or leaving a day early is a nice option to have.