The large bag is on sale, but the baskets are out of stock. Is it possible to attach this to the rear rack or is it not worth getting without the basket?

I just purchased a rad city 3 s/t and it came w/a wooden board on the rear rack.  What is the purpose of that? Is there some accessory I should have that attaches to it for storage like a trunk bag?

Also, are there any after market trunk bags that work w/the rad city rear rack?  I have an Ibera rak pak on my mini, but had to purchase the Ibera rack to go with it. I would obviously prefer to be able to use the rear rack that's arleady on the City if possible.

Any advice appreciated!

There have been lots of suggestions on how to load the mini into the back of a van or suv using a 50 gal. tote with wheels. My question is: how to get the bike INTO the tote by yourself if you can't deadlift almost 70 lbs?