If you guys go to Trogir area, I would reccomend you to visit Max-Rent Water Sports Centre (www.max-rent.com / facebook.com/MaxRentTrogir). Staff is proffessional and friendly. You can drive jet skis, fly with parachute or enjoy numerous other water sport activities such as tubing, banana ride or water skiing!
Tróia is a town and peninsula not that far from Lisbon but already in quiet, natural environment. Surrounded by water and beautiful beaches, it's an amazing place to go for a city runaway.