They will be in rehearsal hall(s) for a while. One of the early activities is typically the recording of music tapes (singing, overature, etc--this is referred to as laying the tracks) and this activity will typically be done early.  That way there is time to make changes if necessary and also it gives the director and chorographer etc a more precise estimate of performance time and in some instances these tapes are used for practicing  choropgraphy steps, stage positions, the placement of movement marks etc.

Though Laura knows the production's script and lyrics that she has used before at Chanhassen, there will likely be changes made and she will need to both forget the old and remember the new. This is sometimes more difficult than learning a new script or lyrics as one can get confused at the changes and old habits are hard to break.

Sometimes the changes are very minor. Eg., some shows singing the Sandra Dee song sing, "I don't swear or rat my haid..." but some shows have sung, "I swear I don't rat my hair..." Largely a matter of choice by the director and perhaps even to meet the preference of a performer. Also  the exact order of songs can sometimes be changed.

Many performers find the tech rehearsals (on the real stage and working on getting good sound amplification where needed, lighting to match stage movement, scenery setup, removal and shifting of flats etc) a lot of fun, but they can also involve a lot of standing around and retries to make the flow work just right. In other words, hard work.  Even the choreography, so to speak, of curtain calls has to be worked out. Even the choreography, so to speak, of curtain calls has to be established and practiced.

Sounds like fun if one could be a mouse in the corner and watch.