Booked the trip via Laganas travel agent (much cheaper than hotel rep.). An early coach pickup (about 7am) necessary to take us to the Zakynthos Harbour (make sure which coach company is taking you) but good ferry trip (about 1 hour) from Zakynthos to Kilini on mainland Greece, followed by 60km coach to Olympia. Excellent archaeological site with a lot of remains to see, followed by tour inside nearby modern museum. Very good guide, lasted about 2 hours. Not so suitable for youngsters unless they're keen on history. Walk/run on the original 2300 year old Olympic track!!
Time for a bit of shopping afterwards, though much the same as in other tourist resorts.

An enjoyable full day trip by coach, booked with a local TEZ (Zakynthos Tourist Board) travel shop (cheaper than hotel rep.), but couldn't visit Blue Caves due to weather because Island authorities forbid any boat trips if it's too rough (quite sensible!). Saw many interesting sights. Stopped for lunch break in a remote village. Good guide. Opportunity for shopping at one or two stops but could be a little pestered for trade (maybe because it was nearly the end of the season and they wanted to reduce their stock??). Maybe not so suitable for children.

Since our accomodation was here we saw Laganas quite often!! Of all the places visited on the island this seemed to have the greatest number of shops & restaurants (more than in the capital of Zakynthos Town). Obviously restaurants are out to tempt you with their food, but they don't over-hassle you (depending on your age?). Wide variety of tourist shops with good prices. A few 'sports-like' activity places for kids. Lovely beach.