Nice job!
As for the booster...
No, you do not need to remove the dash. It is a fairly simple job.
From memory...2 bolts to disconnect the master cylinder, crawl under dash and remove 4 bolts that hold booster, plunger shaft has a pin that holds it that you remove. There are a few hard lines under the hood that you need to remove the mounting clamps so they can be moved to the side a bit...then wiggle, twist and manipulate the booster back (to clear the plunger shaft) and out through the top. Reverse for reinstall. There is a spacer you need to transfer from the old booster to the new one...don't forget to do it before putting the new one in.