for just two bikes you might be able to hang from the ladder
what I would do most likely, is look into a rack for the toad. that way if while at a destination you want to tote the bikes to a trail or something, it's no big deal....More versatile I think...
I don't know why you think it would be out of the question.... I've seen tire mounted racks before...or a hitch extender.... or a roof rack. Probably lots of options.
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