You will be ok in mind-October, but note that RR is implementing a "timed entry permit system" for the loop road starting on November 3 to control crowds during peak season (10/1 through 5/1). $2 each day, in addition to your entry fee (if any). Best to purchase online ahead of time. We will see how fast the permits go, but I'm betting they will go rapidly. (Should be a very good time indeed for locals that have always been able to head in whenever they get free time with no notice, but alas such are the times we live in.) Since 1/1/20 late exit permits have been handled online through Recreation.gov. I agree it is definitely a good idea to get on of those on any potentially long days, but also note that late exit permits are not being issued right now due to the pandemic. No word on when they will recommence.