[B_and_D]

We have a truck, and we have neither. Sometimes we take along a locking tool box. We like to take along our bikes and other big stuff that wouldn't fit into either a shell or a tonneau.

If you have the tonneau, why not take a couple of trips in it and see how it works?

Does your DW like to drive the truck & TM? A shell would make it harder to see behind as you drive. The last time we took our TM out I asked DH to take off the tool box because it makes it harder for me to see out the back window. I'm not as tall as he is (almost a foot shorter), but I do like to tow the TM as long as I'm driving forward and can see the traffic behind me.

We're in "sunny" CA, so we don't have to worry about stuff in the back getting wet during our summer camping trips. Is this a concern for you? Does your DW want to bring a lot of stuff along? Does she feel a need to have things locked up so that people don't steal things? Do you have pets?