River Kayaking in Roseau

I am trying to decide between

Dominica Shore Excursion: River to Ocean Kayaking Adventure

with VIATOR

and

RIVER TO OCEAN KAYAKING ADVENTURE http://www.shoretrips.com/excursion/ship-5285319-dmc-020350/ms-noordam-2-28-2014/dominica-roseau/river-to-ocean-kayaking-adventure

with SHORE TRIPS.

Any one been on either one? I'm leaning away from river tubing as I feel that one of my friends who has mobility issues would have a difficult time.

Thanks in advance for any suggestions or help!

If any one would like to join in on this excursion it would be $62.00 per person with Shore Trips.....any takers?!?!