Perhaps the OP is not in the first flush of youth ( welcome...).
The transom/rudder step is a good trick as it will always be there.
I carry half inflated floor less round tail dinghy on coach roof, as I did when I had a 21ft Corribee too.
The addition of wooden floor and transom does make them both wider and bulkier though they may still sit under the boom if you take 'most' but not 'all' of the air out. To inflate lie it across the guardrails forward, this usually gives you standing room as well for inflating, then give it a push!