Sounds great! You can get more information on van transfers here:
The last blog contains a lot of information that might be of benefit to you in doing your research. Don't worry about meeting other travelers. You're sure to meet a lot in town and some when you join any of the tours. A lot of travelers in El Nido came with the same thing in mind. If you're likewise up for some adventure, I highly recommend renting a kayak and explore nearby Cadlao island and it's empty beaches and coves.
I got my dry bag at SM. There are various sizes available costing not more than P700. I got a medium one for less than P500. It's much cheaper than the branded ones that run into the thousands i.e. Rubber Ducky, Body Glove, etc. but it was able to serve it's purpose very well. El Nido Art Cafe also sells them for just little more.