We really enjoyed all the trips.
I would do the MATHRAKI & OTHONI trip myself - good boat trip - you stop in Sidari as well to pick up and drop off.
We found enough to do - a drink in the taverna / lunch etc... a hike around the area or sit on the beach, quite pleasant and some nice things to see.
I would do PALEOKASTRITSA by coach or car where you can get the wonderful views from the side of the mountain - before stopping in the town.
I like the PALEOKASTRITSA by boat as a second option where they drop you on the harbour and you hike into the town centre.
ERICUSA ISLAND - again in / out Sidari and views of Canal D'Amour, ERICUSA itself - some lovely Tavernas - nice sights etc if you like walking,
but it would drag a bit if you don't like walking too far. Quiet.
Tony