Since no one has responded to your post, I thought I would give it a go!
We've only stayed at HH once but are looking forward to our visit in November. Anyway, I don't think there is a bad building to stay at because the resort is pretty compact. I think you should consider what you are most interested in being closest to and request a building accordingly. We wanted a non-smoking marsh view on the first floor (you will have to navigate one flight of stairs for a "first floor" unit and of course two flights of stairs for a "second floor" unit). A very nice CM put us in building 31. She said she always puts her mother in that building. It's a little bit aways from the hustle and bustle but you are a short walk to the pool, activities center, campfire, fishing pier and snack bar. I think we timed it to be about 2 or 3 minute walk. You are a little further from the main lodge where you check in and where Big Murgy's Den is located so if that is important to you and your family I'd request a building near the lodge.
The resort has mostly 2 bedroom units and you didn't say what type of villa you had reserved but I hope this helps. We are again hoping for building 31 but want to be near my family who will be staying in a studio so that may affect where we are assigned. If you have any other questions about Hilton Head, don't hesitate to ask. We love it there!