This exact thing happened to me last June: early entry, headed out to ROTR, saw the cast members at the ride entrance announcing it was not in service. I continued straight on the "long way" to Slinky and only had a brief wait there. (It looks like tons of people, but not really because the interior queue is not in use yet.) Then I went to TSM and that took a while but only because a track, or maybe two tracks, were down. Later in the day, the wait for ROTR moderated so it all kinda worked out anyway. I recommend having a plan in place to pivot immediately in the event ROTR does not operate for EE.