Outdoorsy in Tonga

Hello a friend and I will be volunteering in Nuko-ulofa, allowing us a week to travel around.

We love hiking, swimming, kayaking, biking...

1) Does anyone know of a good kayaking rental place and an interesting day trip?

2) What about biking? Any rental stores anywhere?

3) And any hikes on this or neighbouring islands.

4) Any other suggestions would be greatly appreciated...

Thanks gals and guys!

WD