"Is it any trouble to get from Spain to Portugal???"
No problem, good communications and there is no borders (no passport controls) since both countries are part of the EU.
"Can anyone recommend a killer coastal trek???"
Don't know sorry
"What/where is the "Rock"?"
I guess it is Gibraltar (el Peñón de Gibraltar), which is a british colony in the south of Spain.
"Is it any trouble to go to Morocco for a day?"
Don't know.
"What would the best way to do that from Spain?"
For sure the ferries (boats which can carry vehicles) that travel from Algeciras and other important southern cities.
Regards.
Fernando