Route from San Diego (CA) to Sedona (AZ)

I wouldn't rush my first trip in a RV - especially a used RV. I would take it slow and keep and eye/ear out for anything that maybe wrong - use the extra time to get familiar with the rig and each of it's components. Good idea to bring some basic tools in case you need to fix something en-route.

Some people love to plan trips to the nth degree - others like me tend to wing it and drive until they see something interesting or get tired. RV allows you the luxury to do either.