Solothurn/Morges advise please

Afternoon all.

Hopefully David will see this as I believe he has been there, which site in Switzerland would be more suited for an 8 year old girl, Solothurn or Morges,

They are planning on taking their bikes, and wish to access the lakes and mountains, and also have a few excursions if at  all possible, we have noted that there are local swimming pools close to both sites, but are looking for some reviews .

Any assistance would be greatly appreciated , as I am assisting this lady and her Daughter with making their booking.