This is anecdotal report of how I handled one month of no charging.
We were going on vacation for a month in a place where I could not depend on nightly charging. So to start the trip (500 miles) I immediately set the car to Hybrid Auto (no Pure) and drove in B mode. when the battery range dropped to 25 miles, I switched to Hybrid Hold. Every time we used the car for the entire month we started in Hybrid Hold and drove in B. That maintained the charge in the battery at 20 mikes or so, My service manager cautioned me about operating at 0 miles without charging for a month. This worked fairly well except when we ran in Hybrid Auto and D mode. Then while on a long straight stretch of highway (I95) I ran in charge mode, seemed to only use 3 mpg more than usual, to charge back up to 25 miles of range. When we returned home charged to full overnight. Everything seems to be working fine.

No of this was scientific just hunches based upon what I could glean from the manual and conversations with service and sales personnel.

YMMV

Mike