Yes a queen mattress fit in a 5x8 U-Haul trailer.
The 5x8 enclosed U Haul Trailer can easily fit a queen sized mattress inside as it's pretty roomy.
There are 200 cubic feet of loading space in the 5x8 U Haul Trailer.
I rented a 5x8 U Haul enclosed Trailer and had plenty of room when putting the Queen Sized Mattress inside of it.
It's a very easy tow trailer and has plenty of room for the mattress and other belongings that you want to haul inside of it.
A U Haul 5x8 enclosed trailer can hold a queen-size bed and tow up to 1,800 lbs of weight.
There is more than 200 cubic feet of loading space in the U Haul enclosed cargo trailer which means there is extra space for you that is easy to tow.
Towing a U Haul Trailer is pretty easy and you just need to make sure you have the right size vehicle, hitch ball size etc.
If you've never towed or backed a trailer before you should practice in a large parking lot or practice around your town a bit before you head off on the road with the trailer.