What is the density (in lbs) of the twin size?
It is a 3# density memory foam.
Trying to find a mattress topper that can easily be transported. Can you easily roll it up?
These can be rolled up, but they will still be fairly bulky unless you are able to compress them. I would recommend a 2" topper or a convoluted topper for transport.
Really they are manufactured to be put on your bed and not moved. So I wouldn’t say that they are easily transported.