For those of you out there that don’t think this is possible.
I only had to strap it to the top because this tree was too tall to fit inside.
Now I have a fair number of miles on my car and really don’t car about the odd scratch or sap. If that bothers you, then you could put down a blanket or something. Gabe did once, but I can’t find the picture. Maybe he’ll be kind enough to link it up for us in the comments ;)