Hi, mwdesign -
I hate that you’re running into this to the point of starting over. How many blog entries do you have?
Yes, you can back-date entries by simply changing those in the entry date calendar, see the attached screenshot.
Unfortunately this may bite you again on future updates, especially if you keep running into a max_execution_time issue. So you may want to get that local install up and running so that you can get past this.